/*
    * Copyright 2016 The Netty Project
    *
    * The Netty Project licenses this file to you under the Apache License,
    * version 2.0 (the "License"); you may not use this file except in compliance
    * with the License. You may obtain a copy of the License at:
    *
    *   https://www.apache.org/licenses/LICENSE-2.0
    *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
   * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
   * License for the specific language governing permissions and limitations
   * under the License.
   */
  package io.netty.handler.ssl;
  
  import io.netty.buffer.ByteBuf;
  import io.netty.buffer.ByteBufAllocator;
  import io.netty.handler.ssl.util.LazyJavaxX509Certificate;
  import io.netty.handler.ssl.util.LazyX509Certificate;
  import io.netty.internal.tcnative.AsyncTask;
  import io.netty.internal.tcnative.Buffer;
  import io.netty.internal.tcnative.SSL;
  import io.netty.util.AbstractReferenceCounted;
  import io.netty.util.CharsetUtil;
  import io.netty.util.ReferenceCounted;
  import io.netty.util.ResourceLeakDetector;
  import io.netty.util.ResourceLeakDetectorFactory;
  import io.netty.util.ResourceLeakTracker;
  import io.netty.util.internal.EmptyArrays;
  import io.netty.util.internal.PlatformDependent;
  import io.netty.util.internal.StringUtil;
  import io.netty.util.internal.SuppressJava6Requirement;
  import io.netty.util.internal.ThrowableUtil;
  import io.netty.util.internal.UnstableApi;
  import io.netty.util.internal.logging.InternalLogger;
  import io.netty.util.internal.logging.InternalLoggerFactory;
  
  import java.nio.ByteBuffer;
  import java.nio.ReadOnlyBufferException;
  import java.security.Principal;
  import java.security.cert.Certificate;
  import java.util.Arrays;
  import java.util.Collection;
  import java.util.Collections;
  import java.util.HashSet;
  import java.util.LinkedHashSet;
  import java.util.List;
  import java.util.Map;
  import java.util.Set;
  import java.util.concurrent.ConcurrentHashMap;
  import java.util.concurrent.locks.Lock;
  
  import javax.crypto.spec.SecretKeySpec;
  import javax.net.ssl.SSLEngine;
  import javax.net.ssl.SSLEngineResult;
  import javax.net.ssl.SSLException;
  import javax.net.ssl.SSLHandshakeException;
  import javax.net.ssl.SSLParameters;
  import javax.net.ssl.SSLPeerUnverifiedException;
  import javax.net.ssl.SSLSession;
  import javax.net.ssl.SSLSessionBindingEvent;
  import javax.net.ssl.SSLSessionBindingListener;
  import javax.security.cert.X509Certificate;
  
  import static io.netty.handler.ssl.OpenSsl.memoryAddress;
  import static io.netty.handler.ssl.SslUtils.SSL_RECORD_HEADER_LENGTH;
  import static io.netty.util.internal.EmptyArrays.EMPTY_STRINGS;
  import static io.netty.util.internal.ObjectUtil.checkNotNull;
  import static io.netty.util.internal.ObjectUtil.checkNotNullArrayParam;
  import static io.netty.util.internal.ObjectUtil.checkNotNullWithIAE;
  import static java.lang.Integer.MAX_VALUE;
  import static java.lang.Math.min;
  import static javax.net.ssl.SSLEngineResult.HandshakeStatus.FINISHED;
  import static javax.net.ssl.SSLEngineResult.HandshakeStatus.NEED_TASK;
  import static javax.net.ssl.SSLEngineResult.HandshakeStatus.NEED_UNWRAP;
  import static javax.net.ssl.SSLEngineResult.HandshakeStatus.NEED_WRAP;
  import static javax.net.ssl.SSLEngineResult.HandshakeStatus.NOT_HANDSHAKING;
  import static javax.net.ssl.SSLEngineResult.Status.BUFFER_OVERFLOW;
  import static javax.net.ssl.SSLEngineResult.Status.BUFFER_UNDERFLOW;
  import static javax.net.ssl.SSLEngineResult.Status.CLOSED;
  import static javax.net.ssl.SSLEngineResult.Status.OK;
  
  /**
   * Implements a {@link SSLEngine} using
   * <a href="https://www.openssl.org/docs/crypto/BIO_s_bio.html#EXAMPLE">OpenSSL BIO abstractions</a>.
   * <p>Instances of this class must be {@link #release() released} or else native memory will leak!
   *
   * <p>Instances of this class <strong>must</strong> be released before the {@link ReferenceCountedOpenSslContext}
   * the instance depends upon are released. Otherwise if any method of this class is called which uses the
   * the {@link ReferenceCountedOpenSslContext} JNI resources the JVM may crash.
   */
  public class ReferenceCountedOpenSslEngine extends SSLEngine implements ReferenceCounted, ApplicationProtocolAccessor {
  
      private static final InternalLogger logger = InternalLoggerFactory.getInstance(ReferenceCountedOpenSslEngine.class);
  
      private static final ResourceLeakDetector<ReferenceCountedOpenSslEngine> leakDetector =
              ResourceLeakDetectorFactory.instance().newResourceLeakDetector(ReferenceCountedOpenSslEngine.class);
     private static final int OPENSSL_OP_NO_PROTOCOL_INDEX_SSLV2 = 0;
     private static final int OPENSSL_OP_NO_PROTOCOL_INDEX_SSLV3 = 1;
     private static final int OPENSSL_OP_NO_PROTOCOL_INDEX_TLSv1 = 2;
     private static final int OPENSSL_OP_NO_PROTOCOL_INDEX_TLSv1_1 = 3;
     private static final int OPENSSL_OP_NO_PROTOCOL_INDEX_TLSv1_2 = 4;
     private static final int OPENSSL_OP_NO_PROTOCOL_INDEX_TLSv1_3 = 5;
     private static final int[] OPENSSL_OP_NO_PROTOCOLS = {
             SSL.SSL_OP_NO_SSLv2,
             SSL.SSL_OP_NO_SSLv3,
             SSL.SSL_OP_NO_TLSv1,
             SSL.SSL_OP_NO_TLSv1_1,
             SSL.SSL_OP_NO_TLSv1_2,
             SSL.SSL_OP_NO_TLSv1_3
     };
 
     /**
      * Depends upon tcnative ... only use if tcnative is available!
      */
     static final int MAX_PLAINTEXT_LENGTH = SSL.SSL_MAX_PLAINTEXT_LENGTH;
     /**
      * Depends upon tcnative ... only use if tcnative is available!
      */
     static final int MAX_RECORD_SIZE = SSL.SSL_MAX_RECORD_LENGTH;
 
     private static final SSLEngineResult NEED_UNWRAP_OK = new SSLEngineResult(OK, NEED_UNWRAP, 0, 0);
     private static final SSLEngineResult NEED_UNWRAP_CLOSED = new SSLEngineResult(CLOSED, NEED_UNWRAP, 0, 0);
     private static final SSLEngineResult NEED_WRAP_OK = new SSLEngineResult(OK, NEED_WRAP, 0, 0);
     private static final SSLEngineResult NEED_WRAP_CLOSED = new SSLEngineResult(CLOSED, NEED_WRAP, 0, 0);
     private static final SSLEngineResult CLOSED_NOT_HANDSHAKING = new SSLEngineResult(CLOSED, NOT_HANDSHAKING, 0, 0);
 
     // OpenSSL state
     private long ssl;
     private long networkBIO;
 
     private enum HandshakeState {
         /**
          * Not started yet.
          */
         NOT_STARTED,
         /**
          * Started via unwrap/wrap.
          */
         STARTED_IMPLICITLY,
         /**
          * Started via {@link #beginHandshake()}.
          */
         STARTED_EXPLICITLY,
         /**
          * Handshake is finished.
          */
         FINISHED
     }
 
     private HandshakeState handshakeState = HandshakeState.NOT_STARTED;
     private boolean receivedShutdown;
     private volatile boolean destroyed;
     private volatile String applicationProtocol;
     private volatile boolean needTask;
     private boolean hasTLSv13Cipher;
     private boolean sessionSet;
 
     // Reference Counting
     private final ResourceLeakTracker<ReferenceCountedOpenSslEngine> leak;
     private final AbstractReferenceCounted refCnt = new AbstractReferenceCounted() {
         @Override
         public ReferenceCounted touch(Object hint) {
             if (leak != null) {
                 leak.record(hint);
             }
 
             return ReferenceCountedOpenSslEngine.this;
         }
 
         @Override
         protected void deallocate() {
             shutdown();
             if (leak != null) {
                 boolean closed = leak.close(ReferenceCountedOpenSslEngine.this);
                 assert closed;
             }
             parentContext.release();
         }
     };
 
     private final Set<String> enabledProtocols = new LinkedHashSet<String>();
 
     private volatile ClientAuth clientAuth = ClientAuth.NONE;
 
     private String endpointIdentificationAlgorithm;
     // Store as object as AlgorithmConstraints only exists since java 7.
     private Object algorithmConstraints;
     private List<String> sniHostNames;
 
     // Mark as volatile as accessed by checkSniHostnameMatch(...) and also not specify the SNIMatcher type to allow us
     // using it with java7.
     private volatile Collection<?> matchers;
 
     // SSL Engine status variables
     private boolean isInboundDone;
     private boolean outboundClosed;
 
     final boolean jdkCompatibilityMode;
     private final boolean clientMode;
     final ByteBufAllocator alloc;
     private final OpenSslEngineMap engineMap;
     private final OpenSslApplicationProtocolNegotiator apn;
     private final ReferenceCountedOpenSslContext parentContext;
     private final OpenSslInternalSession session;
     private final ByteBuffer[] singleSrcBuffer = new ByteBuffer[1];
     private final ByteBuffer[] singleDstBuffer = new ByteBuffer[1];
     private final boolean enableOcsp;
     private int maxWrapOverhead;
     private int maxWrapBufferSize;
     private Throwable pendingException;
 
     /**
      * Create a new instance.
      * @param context Reference count release responsibility is not transferred! The callee still owns this object.
      * @param alloc The allocator to use.
      * @param peerHost The peer host name.
      * @param peerPort The peer port.
      * @param jdkCompatibilityMode {@code true} to behave like described in
      *                             https://docs.oracle.com/javase/7/docs/api/javax/net/ssl/SSLEngine.html.
      *                             {@code false} allows for partial and/or multiple packets to be process in a single
      *                             wrap or unwrap call.
      * @param leakDetection {@code true} to enable leak detection of this object.
      */
     ReferenceCountedOpenSslEngine(ReferenceCountedOpenSslContext context, final ByteBufAllocator alloc, String peerHost,
                                   int peerPort, boolean jdkCompatibilityMode, boolean leakDetection,
                                   String endpointIdentificationAlgorithm) {
         super(peerHost, peerPort);
         OpenSsl.ensureAvailability();
         engineMap = context.engineMap;
         enableOcsp = context.enableOcsp;
         this.jdkCompatibilityMode = jdkCompatibilityMode;
         this.alloc = checkNotNull(alloc, "alloc");
         apn = (OpenSslApplicationProtocolNegotiator) context.applicationProtocolNegotiator();
         clientMode = context.isClient();
         this.endpointIdentificationAlgorithm = endpointIdentificationAlgorithm;
 
         if (PlatformDependent.javaVersion() >= 7) {
             session = new ExtendedOpenSslSession(new DefaultOpenSslSession(context.sessionContext())) {
                 private String[] peerSupportedSignatureAlgorithms;
                 private List requestedServerNames;
 
                 @Override
                 public List getRequestedServerNames() {
                     if (clientMode) {
                         return Java8SslUtils.getSniHostNames(sniHostNames);
                     } else {
                         synchronized (ReferenceCountedOpenSslEngine.this) {
                             if (requestedServerNames == null) {
                                 if (isDestroyed()) {
                                     requestedServerNames = Collections.emptyList();
                                 } else {
                                     String name = SSL.getSniHostname(ssl);
                                     if (name == null) {
                                         requestedServerNames = Collections.emptyList();
                                     } else {
                                         // Convert to bytes as we do not want to do any strict validation of the
                                         // SNIHostName while creating it.
                                         requestedServerNames =
                                                 Java8SslUtils.getSniHostName(
                                                         SSL.getSniHostname(ssl).getBytes(CharsetUtil.UTF_8));
                                     }
                                 }
                             }
                             return requestedServerNames;
                         }
                     }
                 }
 
                 @Override
                 public String[] getPeerSupportedSignatureAlgorithms() {
                     synchronized (ReferenceCountedOpenSslEngine.this) {
                         if (peerSupportedSignatureAlgorithms == null) {
                             if (isDestroyed()) {
                                 peerSupportedSignatureAlgorithms = EMPTY_STRINGS;
                             } else {
                                 String[] algs = SSL.getSigAlgs(ssl);
                                 if (algs == null) {
                                     peerSupportedSignatureAlgorithms = EMPTY_STRINGS;
                                 } else {
                                     Set<String> algorithmList = new LinkedHashSet<String>(algs.length);
                                     for (String alg: algs) {
                                         String converted = SignatureAlgorithmConverter.toJavaName(alg);
 
                                         if (converted != null) {
                                             algorithmList.add(converted);
                                         }
                                     }
                                     peerSupportedSignatureAlgorithms = algorithmList.toArray(EMPTY_STRINGS);
                                 }
                             }
                         }
                         return peerSupportedSignatureAlgorithms.clone();
                     }
                 }
 
                 @Override
                 public List<byte[]> getStatusResponses() {
                     byte[] ocspResponse = null;
                     if (enableOcsp && clientMode) {
                         synchronized (ReferenceCountedOpenSslEngine.this) {
                             if (!isDestroyed()) {
                                 ocspResponse = SSL.getOcspResponse(ssl);
                             }
                         }
                     }
                     return ocspResponse == null ?
                             Collections.<byte[]>emptyList() : Collections.singletonList(ocspResponse);
                 }
             };
         } else {
             session = new DefaultOpenSslSession(context.sessionContext());
         }
 
         if (!context.sessionContext().useKeyManager()) {
             session.setLocalCertificate(context.keyCertChain);
         }
 
         Lock readerLock = context.ctxLock.readLock();
         readerLock.lock();
         final long finalSsl;
         try {
             finalSsl = SSL.newSSL(context.ctx, !context.isClient());
         } finally {
             readerLock.unlock();
         }
         synchronized (this) {
             ssl = finalSsl;
             try {
                 networkBIO = SSL.bioNewByteBuffer(ssl, context.getBioNonApplicationBufferSize());
 
                 // Set the client auth mode, this needs to be done via setClientAuth(...) method so we actually call the
                 // needed JNI methods.
                 setClientAuth(clientMode ? ClientAuth.NONE : context.clientAuth);
 
                 assert context.protocols != null;
                 this.hasTLSv13Cipher = context.hasTLSv13Cipher;
 
                 setEnabledProtocols(context.protocols);
 
                 // Use SNI if peerHost was specified and a valid hostname
                 // See https://github.com/netty/netty/issues/4746
                 if (clientMode && SslUtils.isValidHostNameForSNI(peerHost)) {
                     // If on java8 and later we should do some extra validation to ensure we can construct the
                     // SNIHostName later again.
                     if (PlatformDependent.javaVersion() >= 8) {
                         if (Java8SslUtils.isValidHostNameForSNI(peerHost)) {
                             SSL.setTlsExtHostName(ssl, peerHost);
                             sniHostNames = Collections.singletonList(peerHost);
                         }
                     } else {
                         SSL.setTlsExtHostName(ssl, peerHost);
                         sniHostNames = Collections.singletonList(peerHost);
                     }
                 }
 
                 if (enableOcsp) {
                     SSL.enableOcsp(ssl);
                 }
 
                 if (!jdkCompatibilityMode) {
                     SSL.setMode(ssl, SSL.getMode(ssl) | SSL.SSL_MODE_ENABLE_PARTIAL_WRITE);
                 }
 
                 if (isProtocolEnabled(SSL.getOptions(ssl), SSL.SSL_OP_NO_TLSv1_3, SslProtocols.TLS_v1_3)) {
                     final boolean enableTickets = clientMode ?
                             ReferenceCountedOpenSslContext.CLIENT_ENABLE_SESSION_TICKET_TLSV13 :
                             ReferenceCountedOpenSslContext.SERVER_ENABLE_SESSION_TICKET_TLSV13;
                     if (enableTickets) {
                         // We should enable session tickets for stateless resumption when TLSv1.3 is enabled. This
                         // is also done by OpenJDK and without this session resumption does not work at all with
                         // BoringSSL when TLSv1.3 is used as BoringSSL only supports stateless resumption with TLSv1.3:
                         //
                         // See:
                         //  - https://bugs.openjdk.java.net/browse/JDK-8223922
                         //  - https://boringssl.googlesource.com/boringssl/+/refs/heads/master/ssl/tls13_server.cc#104
                         SSL.clearOptions(ssl, SSL.SSL_OP_NO_TICKET);
                     }
                 }
 
                 if (OpenSsl.isBoringSSL() && clientMode) {
                     // If in client-mode and BoringSSL let's allow to renegotiate once as the server may use this
                     // for client auth.
                     //
                     // See https://github.com/netty/netty/issues/11529
                     SSL.setRenegotiateMode(ssl, SSL.SSL_RENEGOTIATE_ONCE);
                 }
                 // setMode may impact the overhead.
                 calculateMaxWrapOverhead();
 
                 // Configure any endpoint verification specified by the SslContext.
                 configureEndpointVerification(endpointIdentificationAlgorithm);
             } catch (Throwable cause) {
                 // Call shutdown so we are sure we correctly release all native memory and also guard against the
                 // case when shutdown() will be called by the finalizer again.
                 shutdown();
 
                 PlatformDependent.throwException(cause);
             }
         }
 
         // Now that everything looks good and we're going to successfully return the
         // object so we need to retain a reference to the parent context.
         parentContext = context;
         parentContext.retain();
 
         // Only create the leak after everything else was executed and so ensure we don't produce a false-positive for
         // the ResourceLeakDetector.
         leak = leakDetection ? leakDetector.track(this) : null;
     }
 
     final synchronized String[] authMethods() {
         if (isDestroyed()) {
             return EMPTY_STRINGS;
         }
         return SSL.authenticationMethods(ssl);
     }
 
     final boolean setKeyMaterial(OpenSslKeyMaterial keyMaterial) throws  Exception {
         synchronized (this) {
             if (isDestroyed()) {
                 return false;
             }
             SSL.setKeyMaterial(ssl, keyMaterial.certificateChainAddress(), keyMaterial.privateKeyAddress());
         }
         session.setLocalCertificate(keyMaterial.certificateChain());
         return true;
     }
 
     final synchronized SecretKeySpec masterKey() {
         if (isDestroyed()) {
             return null;
         }
         return new SecretKeySpec(SSL.getMasterKey(ssl), "AES");
     }
 
     synchronized boolean isSessionReused() {
         if (isDestroyed()) {
             return false;
         }
         return SSL.isSessionReused(ssl);
     }
 
     /**
      * Sets the OCSP response.
      */
     @UnstableApi
     public void setOcspResponse(byte[] response) {
         if (!enableOcsp) {
             throw new IllegalStateException("OCSP stapling is not enabled");
         }
 
         if (clientMode) {
             throw new IllegalStateException("Not a server SSLEngine");
         }
 
         synchronized (this) {
             if (!isDestroyed()) {
                 SSL.setOcspResponse(ssl, response);
             }
         }
     }
 
     /**
      * Returns the OCSP response or {@code null} if the server didn't provide a stapled OCSP response.
      */
     @UnstableApi
     public byte[] getOcspResponse() {
         if (!enableOcsp) {
             throw new IllegalStateException("OCSP stapling is not enabled");
         }
 
         if (!clientMode) {
             throw new IllegalStateException("Not a client SSLEngine");
         }
 
         synchronized (this) {
             if (isDestroyed()) {
                 return EmptyArrays.EMPTY_BYTES;
             }
             return SSL.getOcspResponse(ssl);
         }
     }
 
     @Override
     public final int refCnt() {
         return refCnt.refCnt();
     }
 
     @Override
     public final ReferenceCounted retain() {
         refCnt.retain();
         return this;
     }
 
     @Override
     public final ReferenceCounted retain(int increment) {
         refCnt.retain(increment);
         return this;
     }
 
     @Override
     public final ReferenceCounted touch() {
         refCnt.touch();
         return this;
     }
 
     @Override
     public final ReferenceCounted touch(Object hint) {
         refCnt.touch(hint);
         return this;
     }
 
     @Override
     public final boolean release() {
         return refCnt.release();
     }
 
     @Override
     public final boolean release(int decrement) {
         return refCnt.release(decrement);
     }
 
     // These method will override the method defined by Java 8u251 and later. As we may compile with an earlier
     // java8 version we don't use @Override annotations here.
     public String getApplicationProtocol() {
         return applicationProtocol;
     }
 
     // These method will override the method defined by Java 8u251 and later. As we may compile with an earlier
     // java8 version we don't use @Override annotations here.
     public String getHandshakeApplicationProtocol() {
         return applicationProtocol;
     }
 
     @Override
     public final synchronized SSLSession getHandshakeSession() {
         // Javadocs state return value should be:
         // null if this instance is not currently handshaking, or if the current handshake has not
         // progressed far enough to create a basic SSLSession. Otherwise, this method returns the
         // SSLSession currently being negotiated.
         switch(handshakeState) {
             case NOT_STARTED:
             case FINISHED:
                 return null;
             default:
                 return session;
         }
     }
 
     /**
      * Returns the pointer to the {@code SSL} object for this {@link ReferenceCountedOpenSslEngine}.
      * Be aware that it is freed as soon as the {@link #release()} or {@link #shutdown()} methods are called.
      * At this point {@code 0} will be returned.
      */
     public final synchronized long sslPointer() {
         return ssl;
     }
 
     /**
      * Destroys this engine.
      */
     public final synchronized void shutdown() {
         if (!destroyed) {
             destroyed = true;
             // Let's check if engineMap is null as it could be in theory if we throw an OOME during the construction of
             // ReferenceCountedOpenSslEngine (before we assign the field). This is needed as shutdown() is called from
             // the finalizer as well.
             if (engineMap != null) {
                 engineMap.remove(ssl);
             }
             SSL.freeSSL(ssl);
             ssl = networkBIO = 0;
 
             isInboundDone = outboundClosed = true;
         }
 
         // On shutdown clear all errors
         SSL.clearError();
     }
 
     /**
      * Write plaintext data to the OpenSSL internal BIO
      *
      * Calling this function with src.remaining == 0 is undefined.
      */
     private int writePlaintextData(final ByteBuffer src, int len) {
         final int pos = src.position();
         final int limit = src.limit();
         final int sslWrote;
 
         if (src.isDirect()) {
             sslWrote = SSL.writeToSSL(ssl, bufferAddress(src) + pos, len);
             if (sslWrote > 0) {
                 src.position(pos + sslWrote);
             }
         } else {
             ByteBuf buf = alloc.directBuffer(len);
             try {
                 src.limit(pos + len);
 
                 buf.setBytes(0, src);
                 src.limit(limit);
 
                 sslWrote = SSL.writeToSSL(ssl, memoryAddress(buf), len);
                 if (sslWrote > 0) {
                     src.position(pos + sslWrote);
                 } else {
                     src.position(pos);
                 }
             } finally {
                 buf.release();
             }
         }
         return sslWrote;
     }
 
    synchronized void bioSetFd(int fd) {
         if (!isDestroyed()) {
             SSL.bioSetFd(this.ssl, fd);
         }
     }
 
     /**
      * Write encrypted data to the OpenSSL network BIO.
      */
     private ByteBuf writeEncryptedData(final ByteBuffer src, int len) throws SSLException {
         final int pos = src.position();
         if (src.isDirect()) {
             SSL.bioSetByteBuffer(networkBIO, bufferAddress(src) + pos, len, false);
         } else {
             final ByteBuf buf = alloc.directBuffer(len);
             try {
                 final int limit = src.limit();
                 src.limit(pos + len);
                 buf.writeBytes(src);
                 // Restore the original position and limit because we don't want to consume from `src`.
                 src.position(pos);
                 src.limit(limit);
 
                 SSL.bioSetByteBuffer(networkBIO, memoryAddress(buf), len, false);
                 return buf;
             } catch (Throwable cause) {
                 buf.release();
                 PlatformDependent.throwException(cause);
             }
         }
         return null;
     }
 
     /**
      * Read plaintext data from the OpenSSL internal BIO
      */
     private int readPlaintextData(final ByteBuffer dst) throws SSLException {
         final int sslRead;
         final int pos = dst.position();
         if (dst.isDirect()) {
             sslRead = SSL.readFromSSL(ssl, bufferAddress(dst) + pos, dst.limit() - pos);
             if (sslRead > 0) {
                 dst.position(pos + sslRead);
             }
         } else {
             final int limit = dst.limit();
             final int len = min(maxEncryptedPacketLength0(), limit - pos);
             final ByteBuf buf = alloc.directBuffer(len);
             try {
                 sslRead = SSL.readFromSSL(ssl, memoryAddress(buf), len);
                 if (sslRead > 0) {
                     dst.limit(pos + sslRead);
                     buf.getBytes(buf.readerIndex(), dst);
                     dst.limit(limit);
                 }
             } finally {
                 buf.release();
             }
         }
 
         return sslRead;
     }
 
     /**
      * Visible only for testing!
      */
     final synchronized int maxWrapOverhead() {
         return maxWrapOverhead;
     }
 
     /**
      * Visible only for testing!
      */
     final synchronized int maxEncryptedPacketLength() {
         return maxEncryptedPacketLength0();
     }
 
     /**
      * This method is intentionally not synchronized, only use if you know you are in the EventLoop
      * thread and visibility on {@link #maxWrapOverhead} is achieved via other synchronized blocks.
      */
     final int maxEncryptedPacketLength0() {
         return maxWrapOverhead + MAX_PLAINTEXT_LENGTH;
     }
 
     /**
      * This method is intentionally not synchronized, only use if you know you are in the EventLoop
      * thread and visibility on {@link #maxWrapBufferSize} and {@link #maxWrapOverhead} is achieved
      * via other synchronized blocks.
      * <br>
      * Calculates the max size of a single wrap operation for the given plaintextLength and
      * numComponents.
      */
     final int calculateMaxLengthForWrap(int plaintextLength, int numComponents) {
         return (int) min(maxWrapBufferSize, plaintextLength + (long) maxWrapOverhead * numComponents);
     }
 
     /**
      * This method is intentionally not synchronized, only use if you know you are in the EventLoop
      * thread and visibility on {@link #maxWrapOverhead} is achieved via other synchronized blocks.
      * <br>
      * Calculates the size of the out net buf to create for the given plaintextLength and numComponents.
      * This is not related to the max size per wrap, as we can wrap chunks at a time into one out net buf.
      */
     final int calculateOutNetBufSize(int plaintextLength, int numComponents) {
         return (int) min(MAX_VALUE, plaintextLength + (long) maxWrapOverhead * numComponents);
     }
 
     final synchronized int sslPending() {
         return sslPending0();
     }
 
     /**
      * It is assumed this method is called in a synchronized block (or the constructor)!
      */
     private void calculateMaxWrapOverhead() {
         maxWrapOverhead = SSL.getMaxWrapOverhead(ssl);
 
         // maxWrapBufferSize must be set after maxWrapOverhead because there is a dependency on this value.
         // If jdkCompatibility mode is off we allow enough space to encrypt 16 buffers at a time. This could be
         // configurable in the future if necessary.
         maxWrapBufferSize = jdkCompatibilityMode ? maxEncryptedPacketLength0() : maxEncryptedPacketLength0() << 4;
     }
 
     private int sslPending0() {
         // OpenSSL has a limitation where if you call SSL_pending before the handshake is complete OpenSSL will throw a
         // "called a function you should not call" error. Using the TLS_method instead of SSLv23_method may solve this
         // issue but this API is only available in 1.1.0+ [1].
         // [1] https://www.openssl.org/docs/man1.1.0/ssl/SSL_CTX_new.html
         return handshakeState != HandshakeState.FINISHED ? 0 : SSL.sslPending(ssl);
     }
 
     private boolean isBytesAvailableEnoughForWrap(int bytesAvailable, int plaintextLength, int numComponents) {
         return bytesAvailable - (long) maxWrapOverhead * numComponents >= plaintextLength;
     }
 
     @Override
     public final SSLEngineResult wrap(
             final ByteBuffer[] srcs, int offset, final int length, final ByteBuffer dst) throws SSLException {
         // Throw required runtime exceptions
         checkNotNullWithIAE(srcs, "srcs");
         checkNotNullWithIAE(dst, "dst");
 
         if (offset >= srcs.length || offset + length > srcs.length) {
             throw new IndexOutOfBoundsException(
                     "offset: " + offset + ", length: " + length +
                             " (expected: offset <= offset + length <= srcs.length (" + srcs.length + "))");
         }
 
         if (dst.isReadOnly()) {
             throw new ReadOnlyBufferException();
         }
 
         synchronized (this) {
             if (isOutboundDone()) {
                 // All drained in the outbound buffer
                 return isInboundDone() || isDestroyed() ? CLOSED_NOT_HANDSHAKING : NEED_UNWRAP_CLOSED;
             }
 
             int bytesProduced = 0;
             ByteBuf bioReadCopyBuf = null;
             try {
                 // Setup the BIO buffer so that we directly write the encryption results into dst.
                 if (dst.isDirect()) {
                     SSL.bioSetByteBuffer(networkBIO, bufferAddress(dst) + dst.position(), dst.remaining(),
                             true);
                 } else {
                     bioReadCopyBuf = alloc.directBuffer(dst.remaining());
                     SSL.bioSetByteBuffer(networkBIO, memoryAddress(bioReadCopyBuf), bioReadCopyBuf.writableBytes(),
                             true);
                 }
 
                 int bioLengthBefore = SSL.bioLengthByteBuffer(networkBIO);
 
                 // Explicitly use outboundClosed as we want to drain any bytes that are still present.
                 if (outboundClosed) {
                     // If the outbound was closed we want to ensure we can produce the alert to the destination buffer.
                     // This is true even if we not using jdkCompatibilityMode.
                     //
                     // We use a plaintextLength of 2 as we at least want to have an alert fit into it.
                     // https://tools.ietf.org/html/rfc5246#section-7.2
                     if (!isBytesAvailableEnoughForWrap(dst.remaining(), 2, 1)) {
                         return new SSLEngineResult(BUFFER_OVERFLOW, getHandshakeStatus(), 0, 0);
                     }
 
                     // There is something left to drain.
                     // See https://github.com/netty/netty/issues/6260
                     bytesProduced = SSL.bioFlushByteBuffer(networkBIO);
                     if (bytesProduced <= 0) {
                         return newResultMayFinishHandshake(NOT_HANDSHAKING, 0, 0);
                     }
                     // It is possible when the outbound was closed there was not enough room in the non-application
                     // buffers to hold the close_notify. We should keep trying to close until we consume all the data
                     // OpenSSL can give us.
                     if (!doSSLShutdown()) {
                         return newResultMayFinishHandshake(NOT_HANDSHAKING, 0, bytesProduced);
                     }
                     bytesProduced = bioLengthBefore - SSL.bioLengthByteBuffer(networkBIO);
                     return newResultMayFinishHandshake(NEED_WRAP, 0, bytesProduced);
                 }
 
                 // Flush any data that may be implicitly generated by OpenSSL (handshake, close, etc..).
                 SSLEngineResult.HandshakeStatus status = NOT_HANDSHAKING;
                 HandshakeState oldHandshakeState = handshakeState;
 
                 // Prepare OpenSSL to work in server mode and receive handshake
                 if (handshakeState != HandshakeState.FINISHED) {
                     if (handshakeState != HandshakeState.STARTED_EXPLICITLY) {
                         // Update accepted so we know we triggered the handshake via wrap
                         handshakeState = HandshakeState.STARTED_IMPLICITLY;
                     }
 
                     // Flush any data that may have been written implicitly during the handshake by OpenSSL.
                     bytesProduced = SSL.bioFlushByteBuffer(networkBIO);
 
                     if (pendingException != null) {
                         // TODO(scott): It is possible that when the handshake failed there was not enough room in the
                         // non-application buffers to hold the alert. We should get all the data before progressing on.
                         // However I'm not aware of a way to do this with the OpenSSL APIs.
                         // See https://github.com/netty/netty/issues/6385.
 
                         // We produced / consumed some data during the handshake, signal back to the caller.
                         // If there is a handshake exception and we have produced data, we should send the data before
                         // we allow handshake() to throw the handshake exception.
                         //
                         // When the user calls wrap() again we will propagate the handshake error back to the user as
                         // soon as there is no more data to was produced (as part of an alert etc).
                         if (bytesProduced > 0) {
                             return newResult(NEED_WRAP, 0, bytesProduced);
                         }
                         // Nothing was produced see if there is a handshakeException that needs to be propagated
                         // to the caller by calling handshakeException() which will return the right HandshakeStatus
                         // if it can "recover" from the exception for now.
                         return newResult(handshakeException(), 0, 0);
                     }
 
                     status = handshake();
 
                     // Handshake may have generated more data, for example if the internal SSL buffer is small
                     // we may have freed up space by flushing above.
                     bytesProduced = bioLengthBefore - SSL.bioLengthByteBuffer(networkBIO);
 
                     if (status == NEED_TASK) {
                         return newResult(status, 0, bytesProduced);
                     }
 
                     if (bytesProduced > 0) {
                         // If we have filled up the dst buffer and we have not finished the handshake we should try to
                         // wrap again. Otherwise we should only try to wrap again if there is still data pending in
                         // SSL buffers.
                         return newResult(mayFinishHandshake(status != FINISHED ?
                                          bytesProduced == bioLengthBefore ? NEED_WRAP :
                                          getHandshakeStatus(SSL.bioLengthNonApplication(networkBIO)) : FINISHED),
                                          0, bytesProduced);
                     }
 
                     if (status == NEED_UNWRAP) {
                         // Signal if the outbound is done or not.
                         return isOutboundDone() ? NEED_UNWRAP_CLOSED : NEED_UNWRAP_OK;
                     }
 
                     // Explicit use outboundClosed and not outboundClosed() as we want to drain any bytes that are
                     // still present.
                     if (outboundClosed) {
                         bytesProduced = SSL.bioFlushByteBuffer(networkBIO);
                         return newResultMayFinishHandshake(status, 0, bytesProduced);
                     }
                 }
 
                 final int endOffset = offset + length;
                 if (jdkCompatibilityMode ||
                         // If the handshake was not finished before we entered the method, we also ensure we only
                         // wrap one record. We do this to ensure we not produce any extra data before the caller
                         // of the method is able to observe handshake completion and react on it.
                         oldHandshakeState != HandshakeState.FINISHED) {
                     int srcsLen = 0;
                     for (int i = offset; i < endOffset; ++i) {
                         final ByteBuffer src = srcs[i];
                         if (src == null) {
                             throw new IllegalArgumentException("srcs[" + i + "] is null");
                         }
                         if (srcsLen == MAX_PLAINTEXT_LENGTH) {
                             continue;
                         }
 
                         srcsLen += src.remaining();
                         if (srcsLen > MAX_PLAINTEXT_LENGTH || srcsLen < 0) {
                             // If srcLen > MAX_PLAINTEXT_LENGTH or secLen < 0 just set it to MAX_PLAINTEXT_LENGTH.
                             // This also help us to guard against overflow.
                             // We not break out here as we still need to check for null entries in srcs[].
                             srcsLen = MAX_PLAINTEXT_LENGTH;
                         }
                     }
 
                     // jdkCompatibilityMode will only produce a single TLS packet, and we don't aggregate src buffers,
                     // so we always fix the number of buffers to 1 when checking if the dst buffer is large enough.
                     if (!isBytesAvailableEnoughForWrap(dst.remaining(), srcsLen, 1)) {
                         return new SSLEngineResult(BUFFER_OVERFLOW, getHandshakeStatus(), 0, 0);
                     }
                 }
 
                 // There was no pending data in the network BIO -- encrypt any application data
                 int bytesConsumed = 0;
                 assert bytesProduced == 0;
 
                 // Flush any data that may have been written implicitly by OpenSSL in case a shutdown/alert occurs.
                 bytesProduced = SSL.bioFlushByteBuffer(networkBIO);
 
                 if (bytesProduced > 0) {
                     return newResultMayFinishHandshake(status, bytesConsumed, bytesProduced);
                 }
                 // There was a pending exception that we just delayed because there was something to produce left.
                 // Throw it now and shutdown the engine.
                 if (pendingException != null) {
                     Throwable error = pendingException;
                     pendingException = null;
                     shutdown();
                     // Throw a new exception wrapping the pending exception, so the stacktrace is meaningful and
                     // contains all the details.
                     throw new SSLException(error);
                 }
 
                 for (; offset < endOffset; ++offset) {
                     final ByteBuffer src = srcs[offset];
                     final int remaining = src.remaining();
                     if (remaining == 0) {
                         continue;
                     }
 
                     final int bytesWritten;
                     if (jdkCompatibilityMode) {
                         // Write plaintext application data to the SSL engine. We don't have to worry about checking
                         // if there is enough space if jdkCompatibilityMode because we only wrap at most
                         // MAX_PLAINTEXT_LENGTH and we loop over the input before hand and check if there is space.
                         bytesWritten = writePlaintextData(src, min(remaining, MAX_PLAINTEXT_LENGTH - bytesConsumed));
                     } else {
                         // OpenSSL's SSL_write keeps state between calls. We should make sure the amount we attempt to
                         // write is guaranteed to succeed so we don't have to worry about keeping state consistent
                         // between calls.
                         final int availableCapacityForWrap = dst.remaining() - bytesProduced - maxWrapOverhead;
                         if (availableCapacityForWrap <= 0) {
                             return new SSLEngineResult(BUFFER_OVERFLOW, getHandshakeStatus(), bytesConsumed,
                                     bytesProduced);
                         }
                         bytesWritten = writePlaintextData(src, min(remaining, availableCapacityForWrap));
                     }
 
                     // Determine how much encrypted data was generated.
                     //
                     // Even if SSL_write doesn't consume any application data it is possible that OpenSSL will
                     // produce non-application data into the BIO. For example session tickets....
                     // See https://github.com/netty/netty/issues/10041
                     final int pendingNow = SSL.bioLengthByteBuffer(networkBIO);
                     bytesProduced += bioLengthBefore - pendingNow;
                     bioLengthBefore = pendingNow;
 
                     if (bytesWritten > 0) {
                         bytesConsumed += bytesWritten;
 
                         if (jdkCompatibilityMode || bytesProduced == dst.remaining()) {
                             return newResultMayFinishHandshake(status, bytesConsumed, bytesProduced);
                         }
                     } else {
                         int sslError = SSL.getError(ssl, bytesWritten);
                         if (sslError == SSL.SSL_ERROR_ZERO_RETURN) {
                             // This means the connection was shutdown correctly, close inbound and outbound
                             if (!receivedShutdown) {
                                 closeAll();
 
                                 bytesProduced += bioLengthBefore - SSL.bioLengthByteBuffer(networkBIO);
 
                                 // If we have filled up the dst buffer and we have not finished the handshake we should
                                 // try to wrap again. Otherwise we should only try to wrap again if there is still data
                                 // pending in SSL buffers.
                                 SSLEngineResult.HandshakeStatus hs = mayFinishHandshake(
                                         status != FINISHED ? bytesProduced == dst.remaining() ? NEED_WRAP
                                                 : getHandshakeStatus(SSL.bioLengthNonApplication(networkBIO))
                                                 : FINISHED);
                                 return newResult(hs, bytesConsumed, bytesProduced);
                             }
 
                             return newResult(NOT_HANDSHAKING, bytesConsumed, bytesProduced);
                         } else if (sslError == SSL.SSL_ERROR_WANT_READ) {
                             // If there is no pending data to read from BIO we should go back to event loop and try
                             // to read more data [1]. It is also possible that event loop will detect the socket has
                             // been closed. [1] https://www.openssl.org/docs/manmaster/ssl/SSL_write.html
                             return newResult(NEED_UNWRAP, bytesConsumed, bytesProduced);
                         } else if (sslError == SSL.SSL_ERROR_WANT_WRITE) {
                             // SSL_ERROR_WANT_WRITE typically means that the underlying transport is not writable
                             // and we should set the "want write" flag on the selector and try again when the
                             // underlying transport is writable [1]. However we are not directly writing to the
                             // underlying transport and instead writing to a BIO buffer. The OpenSsl documentation
                             // says we should do the following [1]:
                             //
                             // "When using a buffering BIO, like a BIO pair, data must be written into or retrieved
                             // out of the BIO before being able to continue."
                             //
                             // In practice this means the destination buffer doesn't have enough space for OpenSSL
                             // to write encrypted data to. This is an OVERFLOW condition.
                             // [1] https://www.openssl.org/docs/manmaster/ssl/SSL_write.html
                             if (bytesProduced > 0) {
                                 // If we produced something we should report this back and let the user call
                                 // wrap again.
                                 return newResult(NEED_WRAP, bytesConsumed, bytesProduced);
                             }
                             return newResult(BUFFER_OVERFLOW, status, bytesConsumed, bytesProduced);
                         } else if (sslError == SSL.SSL_ERROR_WANT_X509_LOOKUP ||
                                 sslError == SSL.SSL_ERROR_WANT_CERTIFICATE_VERIFY ||
                                 sslError == SSL.SSL_ERROR_WANT_PRIVATE_KEY_OPERATION) {
 
                             return newResult(NEED_TASK, bytesConsumed, bytesProduced);
                         } else {
                             // Everything else is considered as error
                             throw shutdownWithError("SSL_write", sslError, SSL.getLastErrorNumber());
                         }
                     }
                 }
                 return newResultMayFinishHandshake(status, bytesConsumed, bytesProduced);
             } finally {
                 SSL.bioClearByteBuffer(networkBIO);
                 if (bioReadCopyBuf == null) {
                     dst.position(dst.position() + bytesProduced);
                 } else {
                     assert bioReadCopyBuf.readableBytes() <= dst.remaining() : "The destination buffer " + dst +
                             " didn't have enough remaining space to hold the encrypted content in " + bioReadCopyBuf;
                     dst.put(bioReadCopyBuf.internalNioBuffer(bioReadCopyBuf.readerIndex(), bytesProduced));
                     bioReadCopyBuf.release();
                 }
             }
         }
     }
 
     private SSLEngineResult newResult(SSLEngineResult.HandshakeStatus hs, int bytesConsumed, int bytesProduced) {
         return newResult(OK, hs, bytesConsumed, bytesProduced);
     }
 
     private SSLEngineResult newResult(SSLEngineResult.Status status, SSLEngineResult.HandshakeStatus hs,
                                       int bytesConsumed, int bytesProduced) {
         // If isOutboundDone, then the data from the network BIO
         // was the close_notify message and all was consumed we are not required to wait
         // for the receipt the peer's close_notify message -- shutdown.
         if (isOutboundDone()) {
             if (isInboundDone()) {
                 // If the inbound was done as well, we need to ensure we return NOT_HANDSHAKING to signal we are done.
                 hs = NOT_HANDSHAKING;
 
                 // As the inbound and the outbound is done we can shutdown the engine now.
                 shutdown();
             }
             return new SSLEngineResult(CLOSED, hs, bytesConsumed, bytesProduced);
         }
         if (hs == NEED_TASK) {
             // Set needTask to true so getHandshakeStatus() will return the correct value.
             needTask = true;
         }
         return new SSLEngineResult(status, hs, bytesConsumed, bytesProduced);
     }
 
     private SSLEngineResult newResultMayFinishHandshake(SSLEngineResult.HandshakeStatus hs,
                                                         int bytesConsumed, int bytesProduced) throws SSLException {
         return newResult(mayFinishHandshake(hs, bytesConsumed, bytesProduced), bytesConsumed, bytesProduced);
     }
 
     private SSLEngineResult newResultMayFinishHandshake(SSLEngineResult.Status status,
                                                         SSLEngineResult.HandshakeStatus hs,
                                                         int bytesConsumed, int bytesProduced) throws SSLException {
         return newResult(status, mayFinishHandshake(hs, bytesConsumed, bytesProduced), bytesConsumed, bytesProduced);
     }
 
     /**
      * Log the error, shutdown the engine and throw an exception.
      */
     private SSLException shutdownWithError(String operation, int sslError, int error) {
         if (logger.isDebugEnabled()) {
             String errorString = SSL.getErrorString(error);
             logger.debug("{} failed with {}: OpenSSL error: {} {}",
                          operation, sslError, error, errorString);
         }
 
         // There was an internal error -- shutdown
         shutdown();
 
         SSLException exception = newSSLExceptionForError(error);
         // If we have a pendingException stored already we should include it as well to help the user debug things.
         if (pendingException != null) {
             exception.initCause(pendingException);
             pendingException = null;
         }
         return exception;
     }
 
     private SSLEngineResult handleUnwrapException(int bytesConsumed, int bytesProduced, SSLException e)
             throws SSLException {
         int lastError = SSL.getLastErrorNumber();
         if (lastError != 0) {
             return sslReadErrorResult(SSL.SSL_ERROR_SSL, lastError, bytesConsumed,
                     bytesProduced);
         }
         throw e;
     }
 
     public final SSLEngineResult unwrap(
             final ByteBuffer[] srcs, int srcsOffset, final int srcsLength,
             final ByteBuffer[] dsts, int dstsOffset, final int dstsLength) throws SSLException {
 
         // Throw required runtime exceptions
         checkNotNullWithIAE(srcs, "srcs");
         if (srcsOffset >= srcs.length
                 || srcsOffset + srcsLength > srcs.length) {
             throw new IndexOutOfBoundsException(
                     "offset: " + srcsOffset + ", length: " + srcsLength +
                             " (expected: offset <= offset + length <= srcs.length (" + srcs.length + "))");
         }
         checkNotNullWithIAE(dsts, "dsts");
         if (dstsOffset >= dsts.length || dstsOffset + dstsLength > dsts.length) {
             throw new IndexOutOfBoundsException(
                     "offset: " + dstsOffset + ", length: " + dstsLength +
                             " (expected: offset <= offset + length <= dsts.length (" + dsts.length + "))");
         }
         long capacity = 0;
         final int dstsEndOffset = dstsOffset + dstsLength;
         for (int i = dstsOffset; i < dstsEndOffset; i ++) {
             ByteBuffer dst = checkNotNullArrayParam(dsts[i], i, "dsts");
             if (dst.isReadOnly()) {
                 throw new ReadOnlyBufferException();
             }
             capacity += dst.remaining();
         }
 
         final int srcsEndOffset = srcsOffset + srcsLength;
         long len = 0;
         for (int i = srcsOffset; i < srcsEndOffset; i++) {
             ByteBuffer src = checkNotNullArrayParam(srcs[i], i, "srcs");
             len += src.remaining();
         }
 
         synchronized (this) {
             if (isInboundDone()) {
                 return isOutboundDone() || isDestroyed() ? CLOSED_NOT_HANDSHAKING : NEED_WRAP_CLOSED;
             }
 
             SSLEngineResult.HandshakeStatus status = NOT_HANDSHAKING;
             HandshakeState oldHandshakeState = handshakeState;
             // Prepare OpenSSL to work in server mode and receive handshake
             if (handshakeState != HandshakeState.FINISHED) {
                 if (handshakeState != HandshakeState.STARTED_EXPLICITLY) {
                     // Update accepted so we know we triggered the handshake via wrap
                     handshakeState = HandshakeState.STARTED_IMPLICITLY;
                 }
 
                 status = handshake();
 
                 if (status == NEED_TASK) {
                     return newResult(status, 0, 0);
                 }
 
                 if (status == NEED_WRAP) {
                     return NEED_WRAP_OK;
                 }
                 // Check if the inbound is considered to be closed if so let us try to wrap again.
                 if (isInboundDone) {
                     return NEED_WRAP_CLOSED;
                 }
             }
 
             int sslPending = sslPending0();
             int packetLength;
             // The JDK implies that only a single SSL packet should be processed per unwrap call [1]. If we are in
             // JDK compatibility mode then we should honor this, but if not we just wrap as much as possible. If there
             // are multiple records or partial records this may reduce thrashing events through the pipeline.
             // [1] https://docs.oracle.com/javase/7/docs/api/javax/net/ssl/SSLEngine.html
             if (jdkCompatibilityMode ||
                     // If the handshake was not finished before we entered the method, we also ensure we only
                     // unwrap one record. We do this to ensure we not produce any extra data before the caller
                     // of the method is able to observe handshake completion and react on it.
                     oldHandshakeState != HandshakeState.FINISHED) {
                 if (len < SSL_RECORD_HEADER_LENGTH) {
                     return newResultMayFinishHandshake(BUFFER_UNDERFLOW, status, 0, 0);
                 }
 
                 packetLength = SslUtils.getEncryptedPacketLength(srcs, srcsOffset);
                 if (packetLength == SslUtils.NOT_ENCRYPTED) {
                     throw new NotSslRecordException("not an SSL/TLS record");
                 }
 
                 assert packetLength >= 0;
 
                 final int packetLengthDataOnly = packetLength - SSL_RECORD_HEADER_LENGTH;
                 if (packetLengthDataOnly > capacity) {
                     // Not enough space in the destination buffer so signal the caller that the buffer needs to be
                     // increased.
                     if (packetLengthDataOnly > MAX_RECORD_SIZE) {
                         // The packet length MUST NOT exceed 2^14 [1]. However we do accommodate more data to support
                         // legacy use cases which may violate this condition (e.g. OpenJDK's SslEngineImpl). If the max
                         // length is exceeded we fail fast here to avoid an infinite loop due to the fact that we
                         // won't allocate a buffer large enough.
                         // [1] https://tools.ietf.org/html/rfc5246#section-6.2.1
                         throw new SSLException("Illegal packet length: " + packetLengthDataOnly + " > " +
                                                 session.getApplicationBufferSize());
                     } else {
                         session.tryExpandApplicationBufferSize(packetLengthDataOnly);
                     }
                     return newResultMayFinishHandshake(BUFFER_OVERFLOW, status, 0, 0);
                 }
 
                 if (len < packetLength) {
                     // We either don't have enough data to read the packet length or not enough for reading the whole
                     // packet.
                     return newResultMayFinishHandshake(BUFFER_UNDERFLOW, status, 0, 0);
                 }
             } else if (len == 0 && sslPending <= 0) {
                 return newResultMayFinishHandshake(BUFFER_UNDERFLOW, status, 0, 0);
             } else if (capacity == 0) {
                 return newResultMayFinishHandshake(BUFFER_OVERFLOW, status, 0, 0);
             } else {
                 packetLength = (int) min(MAX_VALUE, len);
             }
 
             // This must always be the case when we reached here as if not we returned BUFFER_UNDERFLOW.
             assert srcsOffset < srcsEndOffset;
 
             // This must always be the case if we reached here.
             assert capacity > 0;
 
             // Number of produced bytes
             int bytesProduced = 0;
             int bytesConsumed = 0;
             try {
                 srcLoop:
                 for (;;) {
                     ByteBuffer src = srcs[srcsOffset];
                     int remaining = src.remaining();
                     final ByteBuf bioWriteCopyBuf;
                     int pendingEncryptedBytes;
                     if (remaining == 0) {
                         if (sslPending <= 0) {
                             // We must skip empty buffers as BIO_write will return 0 if asked to write something
                             // with length 0.
                             if (++srcsOffset >= srcsEndOffset) {
                                 break;
                             }
                             continue;
                         } else {
                             bioWriteCopyBuf = null;
                             pendingEncryptedBytes = SSL.bioLengthByteBuffer(networkBIO);
                         }
                     } else {
                         // Write more encrypted data into the BIO. Ensure we only read one packet at a time as
                         // stated in the SSLEngine javadocs.
                         pendingEncryptedBytes = min(packetLength, remaining);
                         try {
                             bioWriteCopyBuf = writeEncryptedData(src, pendingEncryptedBytes);
                         } catch (SSLException e) {
                             // Ensure we correctly handle the error stack.
                             return handleUnwrapException(bytesConsumed, bytesProduced, e);
                         }
                     }
                     try {
                         for (;;) {
                             ByteBuffer dst = dsts[dstsOffset];
                             if (!dst.hasRemaining()) {
                                 // No space left in the destination buffer, skip it.
                                 if (++dstsOffset >= dstsEndOffset) {
                                     break srcLoop;
                                 }
                                 continue;
                             }
 
                             int bytesRead;
                             try {
                                 bytesRead = readPlaintextData(dst);
                             } catch (SSLException e) {
                                 // Ensure we correctly handle the error stack.
                                 return handleUnwrapException(bytesConsumed, bytesProduced, e);
                             }
                             // We are directly using the ByteBuffer memory for the write, and so we only know what has
                             // been consumed after we let SSL decrypt the data. At this point we should update the
                             // number of bytes consumed, update the ByteBuffer position, and release temp ByteBuf.
                             int localBytesConsumed = pendingEncryptedBytes - SSL.bioLengthByteBuffer(networkBIO);
                             bytesConsumed += localBytesConsumed;
                             packetLength -= localBytesConsumed;
                             pendingEncryptedBytes -= localBytesConsumed;
                             src.position(src.position() + localBytesConsumed);
 
                             if (bytesRead > 0) {
                                 bytesProduced += bytesRead;
 
                                 if (!dst.hasRemaining()) {
                                     sslPending = sslPending0();
                                     // Move to the next dst buffer as this one is full.
                                     if (++dstsOffset >= dstsEndOffset) {
                                         return sslPending > 0 ?
                                                 newResult(BUFFER_OVERFLOW, status, bytesConsumed, bytesProduced) :
                                                 newResultMayFinishHandshake(isInboundDone() ? CLOSED : OK, status,
                                                         bytesConsumed, bytesProduced);
                                     }
                                 } else if (packetLength == 0 || jdkCompatibilityMode) {
                                     // We either consumed all data or we are in jdkCompatibilityMode and have consumed
                                     // a single TLS packet and should stop consuming until this method is called again.
                                     break srcLoop;
                                 }
                             } else {
                                 int sslError = SSL.getError(ssl, bytesRead);
                                 if (sslError == SSL.SSL_ERROR_WANT_READ || sslError == SSL.SSL_ERROR_WANT_WRITE) {
                                     // break to the outer loop as we want to read more data which means we need to
                                     // write more to the BIO.
                                     break;
                                 } else if (sslError == SSL.SSL_ERROR_ZERO_RETURN) {
                                     // This means the connection was shutdown correctly, close inbound and outbound
                                     if (!receivedShutdown) {
                                         closeAll();
                                     }
                                     return newResultMayFinishHandshake(isInboundDone() ? CLOSED : OK, status,
                                             bytesConsumed, bytesProduced);
                                 } else if (sslError == SSL.SSL_ERROR_WANT_X509_LOOKUP ||
                                         sslError == SSL.SSL_ERROR_WANT_CERTIFICATE_VERIFY ||
                                         sslError == SSL.SSL_ERROR_WANT_PRIVATE_KEY_OPERATION) {
                                     return newResult(isInboundDone() ? CLOSED : OK,
                                             NEED_TASK, bytesConsumed, bytesProduced);
                                 } else {
                                     return sslReadErrorResult(sslError, SSL.getLastErrorNumber(), bytesConsumed,
                                             bytesProduced);
                                 }
                             }
                         }
 
                         if (++srcsOffset >= srcsEndOffset) {
                             break;
                         }
                     } finally {
                         if (bioWriteCopyBuf != null) {
                             bioWriteCopyBuf.release();
                         }
                     }
                 }
             } finally {
                 SSL.bioClearByteBuffer(networkBIO);
                 rejectRemoteInitiatedRenegotiation();
             }
 
             // Check to see if we received a close_notify message from the peer.
             if (!receivedShutdown && (SSL.getShutdown(ssl) & SSL.SSL_RECEIVED_SHUTDOWN) == SSL.SSL_RECEIVED_SHUTDOWN) {
                 closeAll();
             }
 
             return newResultMayFinishHandshake(isInboundDone() ? CLOSED : OK, status, bytesConsumed, bytesProduced);
         }
     }
 
     private boolean needWrapAgain(int stackError) {
         // Check if we have a pending handshakeException and if so see if we need to consume all pending data from the
         // BIO first or can just shutdown and throw it now.
         // This is needed so we ensure close_notify etc is correctly send to the remote peer.
         // See https://github.com/netty/netty/issues/3900
         if (SSL.bioLengthNonApplication(networkBIO) > 0) {
             // we seem to have data left that needs to be transferred and so the user needs
             // call wrap(...). Store the error so we can pick it up later.
             if (pendingException == null) {
                 pendingException = newSSLExceptionForError(stackError);
             } else if (shouldAddSuppressed(pendingException, stackError)) {
                 ThrowableUtil.addSuppressed(pendingException, newSSLExceptionForError(stackError));
             }
             // We need to clear all errors so we not pick up anything that was left on the stack on the next
             // operation. Note that shutdownWithError(...) will cleanup the stack as well so its only needed here.
             SSL.clearError();
             return true;
         }
         return false;
     }
 
     private SSLException newSSLExceptionForError(int stackError) {
         String message = SSL.getErrorString(stackError);
         return handshakeState == HandshakeState.FINISHED ?
                 new OpenSslException(message, stackError) : new OpenSslHandshakeException(message, stackError);
     }
 
     private static boolean shouldAddSuppressed(Throwable target, int errorCode) {
         for (Throwable suppressed: ThrowableUtil.getSuppressed(target)) {
             if (suppressed instanceof NativeSslException &&
                     ((NativeSslException) suppressed).errorCode() == errorCode) {
                 /// An exception with this errorCode was already added before.
                 return false;
             }
         }
         return true;
     }
 
     private SSLEngineResult sslReadErrorResult(int error, int stackError, int bytesConsumed, int bytesProduced)
             throws SSLException {
         if (needWrapAgain(stackError)) {
             // There is something that needs to be send to the remote peer before we can teardown.
             // This is most likely some alert.
             return new SSLEngineResult(OK, NEED_WRAP, bytesConsumed, bytesProduced);
         }
         throw shutdownWithError("SSL_read", error, stackError);
     }
 
     private void closeAll() throws SSLException {
         receivedShutdown = true;
         closeOutbound();
         closeInbound();
     }
 
     private void rejectRemoteInitiatedRenegotiation() throws SSLHandshakeException {
         // As rejectRemoteInitiatedRenegotiation() is called in a finally block we also need to check if we shutdown
         // the engine before as otherwise SSL.getHandshakeCount(ssl) will throw an NPE if the passed in ssl is 0.
         // See https://github.com/netty/netty/issues/7353
         if (!isDestroyed() && (!clientMode && SSL.getHandshakeCount(ssl) > 1 ||
                 // Let's allow to renegotiate once for client auth.
                 clientMode && SSL.getHandshakeCount(ssl) > 2) &&
             // As we may count multiple handshakes when TLSv1.3 is used we should just ignore this here as
             // renegotiation is not supported in TLSv1.3 as per spec.
             !SslProtocols.TLS_v1_3.equals(session.getProtocol()) && handshakeState == HandshakeState.FINISHED) {
             // TODO: In future versions me may also want to send a fatal_alert to the client and so notify it
             // that the renegotiation failed.
             shutdown();
             throw new SSLHandshakeException("remote-initiated renegotiation not allowed");
         }
     }
 
     public final SSLEngineResult unwrap(final ByteBuffer[] srcs, final ByteBuffer[] dsts) throws SSLException {
         return unwrap(srcs, 0, srcs.length, dsts, 0, dsts.length);
     }
 
     private ByteBuffer[] singleSrcBuffer(ByteBuffer src) {
         singleSrcBuffer[0] = src;
         return singleSrcBuffer;
     }
 
     private void resetSingleSrcBuffer() {
         singleSrcBuffer[0] = null;
     }
 
     private ByteBuffer[] singleDstBuffer(ByteBuffer src) {
         singleDstBuffer[0] = src;
         return singleDstBuffer;
     }
 
     private void resetSingleDstBuffer() {
         singleDstBuffer[0] = null;
     }
 
     @Override
     public final synchronized SSLEngineResult unwrap(
             final ByteBuffer src, final ByteBuffer[] dsts, final int offset, final int length) throws SSLException {
         try {
             return unwrap(singleSrcBuffer(src), 0, 1, dsts, offset, length);
         } finally {
             resetSingleSrcBuffer();
         }
     }
 
     @Override
     public final synchronized SSLEngineResult wrap(ByteBuffer src, ByteBuffer dst) throws SSLException {
         try {
             return wrap(singleSrcBuffer(src), dst);
         } finally {
             resetSingleSrcBuffer();
         }
     }
 
     @Override
     public final synchronized SSLEngineResult unwrap(ByteBuffer src, ByteBuffer dst) throws SSLException {
         try {
             return unwrap(singleSrcBuffer(src), singleDstBuffer(dst));
         } finally {
             resetSingleSrcBuffer();
             resetSingleDstBuffer();
         }
     }
 
     @Override
     public final synchronized SSLEngineResult unwrap(ByteBuffer src, ByteBuffer[] dsts) throws SSLException {
         try {
             return unwrap(singleSrcBuffer(src), dsts);
         } finally {
             resetSingleSrcBuffer();
         }
     }
 
     private class TaskDecorator<R extends Runnable> implements Runnable {
         protected final R task;
         TaskDecorator(R task) {
             this.task = task;
         }
 
         @Override
         public void run() {
             runAndResetNeedTask(task);
         }
     }
 
     private final class AsyncTaskDecorator extends TaskDecorator<AsyncTask> implements AsyncRunnable {
         AsyncTaskDecorator(AsyncTask task) {
             super(task);
         }
 
         @Override
         public void run(final Runnable runnable) {
             if (isDestroyed()) {
                 // The engine was destroyed in the meantime, just return.
                 return;
             }
             task.runAsync(new TaskDecorator<Runnable>(runnable));
         }
     }
 
     private void runAndResetNeedTask(Runnable task) {
         // We need to synchronize on the ReferenceCountedOpenSslEngine, we are sure the SSL object
         // will not be freed by the user calling for example shutdown() concurrently.
         synchronized (ReferenceCountedOpenSslEngine.this) {
             try {
                 if (isDestroyed()) {
                     // The engine was destroyed in the meantime, just return.
                     return;
                 }
                 task.run();
                 if (handshakeState != HandshakeState.FINISHED && !isDestroyed()) {
                     // Call SSL.doHandshake(...) If the handshake was not finished yet. This might be needed
                     // to fill the application buffer and so have getHandshakeStatus() return the right value
                     // in this case.
                     if (SSL.doHandshake(ssl) <= 0) {
                         SSL.clearError();
                     }
                 }
             } finally {
                 // The task was run, reset needTask to false so getHandshakeStatus() returns the correct value.
                 needTask = false;
             }
         }
     }
 
     @Override
     public final synchronized Runnable getDelegatedTask() {
         if (isDestroyed()) {
             return null;
         }
         final Runnable task = SSL.getTask(ssl);
         if (task == null) {
             return null;
         }
         if (task instanceof AsyncTask) {
             return new AsyncTaskDecorator((AsyncTask) task);
         }
         return new TaskDecorator<Runnable>(task);
     }
 
     @Override
     public final synchronized void closeInbound() throws SSLException {
         if (isInboundDone) {
             return;
         }
 
         isInboundDone = true;
 
         if (isOutboundDone()) {
             // Only call shutdown if there is no outbound data pending.
             // See https://github.com/netty/netty/issues/6167
             shutdown();
         }
 
         if (handshakeState != HandshakeState.NOT_STARTED && !receivedShutdown) {
             throw new SSLException(
                     "Inbound closed before receiving peer's close_notify: possible truncation attack?");
         }
     }
 
     @Override
     public final synchronized boolean isInboundDone() {
         return isInboundDone;
     }
 
     @Override
     public final synchronized void closeOutbound() {
         if (outboundClosed) {
             return;
         }
 
         outboundClosed = true;
 
         if (handshakeState != HandshakeState.NOT_STARTED && !isDestroyed()) {
             int mode = SSL.getShutdown(ssl);
             if ((mode & SSL.SSL_SENT_SHUTDOWN) != SSL.SSL_SENT_SHUTDOWN) {
                 doSSLShutdown();
             }
         } else {
             // engine closing before initial handshake
             shutdown();
         }
     }
 
     /**
      * Attempt to call {@link SSL#shutdownSSL(long)}.
      * @return {@code false} if the call to {@link SSL#shutdownSSL(long)} was not attempted or returned an error.
      */
     private boolean doSSLShutdown() {
         if (SSL.isInInit(ssl) != 0) {
             // Only try to call SSL_shutdown if we are not in the init state anymore.
             // Otherwise we will see 'error:140E0197:SSL routines:SSL_shutdown:shutdown while in init' in our logs.
             //
             // See also https://hg.nginx.org/nginx/rev/062c189fee20
             return false;
         }
         int err = SSL.shutdownSSL(ssl);
         if (err < 0) {
             int sslErr = SSL.getError(ssl, err);
             if (sslErr == SSL.SSL_ERROR_SYSCALL || sslErr == SSL.SSL_ERROR_SSL) {
                 if (logger.isDebugEnabled()) {
                     int error = SSL.getLastErrorNumber();
                     logger.debug("SSL_shutdown failed: OpenSSL error: {} {}", error, SSL.getErrorString(error));
                 }
                 // There was an internal error -- shutdown
                 shutdown();
                 return false;
             }
             SSL.clearError();
         }
         return true;
     }
 
     @Override
     public final synchronized boolean isOutboundDone() {
         // Check if there is anything left in the outbound buffer.
         // We need to ensure we only call SSL.pendingWrittenBytesInBIO(...) if the engine was not destroyed yet.
         return outboundClosed && (networkBIO == 0 || SSL.bioLengthNonApplication(networkBIO) == 0);
     }
 
     @Override
     public final String[] getSupportedCipherSuites() {
         return OpenSsl.AVAILABLE_CIPHER_SUITES.toArray(EMPTY_STRINGS);
     }
 
     @Override
     public final String[] getEnabledCipherSuites() {
         final String[] extraCiphers;
         final String[] enabled;
         final boolean tls13Enabled;
         synchronized (this) {
             if (!isDestroyed()) {
                 enabled = SSL.getCiphers(ssl);
                 int opts = SSL.getOptions(ssl);
                 if (isProtocolEnabled(opts, SSL.SSL_OP_NO_TLSv1_3, SslProtocols.TLS_v1_3)) {
                     extraCiphers = OpenSsl.EXTRA_SUPPORTED_TLS_1_3_CIPHERS;
                     tls13Enabled = true;
                 } else {
                     extraCiphers = EMPTY_STRINGS;
                     tls13Enabled = false;
                 }
             } else {
                 return EMPTY_STRINGS;
             }
         }
         if (enabled == null) {
             return EMPTY_STRINGS;
         } else {
             Set<String> enabledSet = new LinkedHashSet<String>(enabled.length + extraCiphers.length);
             synchronized (this) {
                 for (int i = 0; i < enabled.length; i++) {
                     String mapped = toJavaCipherSuite(enabled[i]);
                     final String cipher = mapped == null ? enabled[i] : mapped;
                     if ((!tls13Enabled || !OpenSsl.isTlsv13Supported()) && SslUtils.isTLSv13Cipher(cipher)) {
                         continue;
                     }
                     enabledSet.add(cipher);
                 }
                 Collections.addAll(enabledSet, extraCiphers);
             }
             return enabledSet.toArray(EMPTY_STRINGS);
         }
     }
 
     @Override
     public final void setEnabledCipherSuites(String[] cipherSuites) {
         checkNotNull(cipherSuites, "cipherSuites");
 
         final StringBuilder buf = new StringBuilder();
         final StringBuilder bufTLSv13 = new StringBuilder();
 
         CipherSuiteConverter.convertToCipherStrings(Arrays.asList(cipherSuites), buf, bufTLSv13, OpenSsl.isBoringSSL());
         final String cipherSuiteSpec = buf.toString();
         final String cipherSuiteSpecTLSv13 = bufTLSv13.toString();
 
         if (!OpenSsl.isTlsv13Supported() && !cipherSuiteSpecTLSv13.isEmpty()) {
             throw new IllegalArgumentException("TLSv1.3 is not supported by this java version.");
         }
         synchronized (this) {
             hasTLSv13Cipher = !cipherSuiteSpecTLSv13.isEmpty();
             if (!isDestroyed()) {
                 try {
                     // Set non TLSv1.3 ciphers.
                     SSL.setCipherSuites(ssl, cipherSuiteSpec, false);
                     if (OpenSsl.isTlsv13Supported()) {
                         // Set TLSv1.3 ciphers.
                         SSL.setCipherSuites(ssl, OpenSsl.checkTls13Ciphers(logger, cipherSuiteSpecTLSv13), true);
                     }
 
                     // We also need to update the enabled protocols to ensure we disable the protocol if there are
                     // no compatible ciphers left.
                     Set<String> protocols = new HashSet<String>(enabledProtocols);
 
                     // We have no ciphers that are compatible with none-TLSv1.3, let us explicit disable all other
                     // protocols.
                     if (cipherSuiteSpec.isEmpty()) {
                         protocols.remove(SslProtocols.TLS_v1);
                         protocols.remove(SslProtocols.TLS_v1_1);
                         protocols.remove(SslProtocols.TLS_v1_2);
                         protocols.remove(SslProtocols.SSL_v3);
                         protocols.remove(SslProtocols.SSL_v2);
                         protocols.remove(SslProtocols.SSL_v2_HELLO);
                     }
                     // We have no ciphers that are compatible with TLSv1.3, let us explicit disable it.
                     if (cipherSuiteSpecTLSv13.isEmpty()) {
                         protocols.remove(SslProtocols.TLS_v1_3);
                     }
                     // Update the protocols but not cache the value. We only cache when we call it from the user
                     // code or when we construct the engine.
                     setEnabledProtocols0(protocols.toArray(EMPTY_STRINGS), !hasTLSv13Cipher);
                 } catch (Exception e) {
                     throw new IllegalStateException("failed to enable cipher suites: " + cipherSuiteSpec, e);
                 }
             } else {
                 throw new IllegalStateException("failed to enable cipher suites: " + cipherSuiteSpec);
             }
         }
     }
 
     @Override
     public final String[] getSupportedProtocols() {
         return OpenSsl.SUPPORTED_PROTOCOLS_SET.toArray(EMPTY_STRINGS);
     }
 
     @Override
     public final String[] getEnabledProtocols() {
         return enabledProtocols.toArray(EMPTY_STRINGS);
     }
 
     private static boolean isProtocolEnabled(int opts, int disableMask, String protocolString) {
         // We also need to check if the actual protocolString is supported as depending on the openssl API
         // implementations it may use a disableMask of 0 (BoringSSL is doing this for example).
         return (opts & disableMask) == 0 && OpenSsl.SUPPORTED_PROTOCOLS_SET.contains(protocolString);
     }
 
     /**
      * {@inheritDoc}
      * TLS doesn't support a way to advertise non-contiguous versions from the client's perspective, and the client
      * just advertises the max supported version. The TLS protocol also doesn't support all different combinations of
      * discrete protocols, and instead assumes contiguous ranges. OpenSSL has some unexpected behavior
      * (e.g. handshake failures) if non-contiguous protocols are used even where there is a compatible set of protocols
      * and ciphers. For these reasons this method will determine the minimum protocol and the maximum protocol and
      * enabled a contiguous range from [min protocol, max protocol] in OpenSSL.
      */
     @Override
     public final void setEnabledProtocols(String[] protocols) {
         checkNotNullWithIAE(protocols, "protocols");
         synchronized (this) {
             enabledProtocols.clear();
             // Seems like there is no way to explicit disable SSLv2Hello in openssl, so it is always enabled
             enabledProtocols.add(SslProtocols.SSL_v2_HELLO);
 
             Collections.addAll(enabledProtocols, protocols);
 
             setEnabledProtocols0(protocols, !hasTLSv13Cipher);
         }
     }
 
     private void setEnabledProtocols0(String[] protocols, boolean explicitDisableTLSv13) {
         assert Thread.holdsLock(this);
         // This is correct from the API docs
         int minProtocolIndex = OPENSSL_OP_NO_PROTOCOLS.length;
         int maxProtocolIndex = 0;
         for (String p: protocols) {
             if (!OpenSsl.SUPPORTED_PROTOCOLS_SET.contains(p)) {
                 throw new IllegalArgumentException("Protocol " + p + " is not supported.");
             }
             if (p.equals(SslProtocols.SSL_v2)) {
                 if (minProtocolIndex > OPENSSL_OP_NO_PROTOCOL_INDEX_SSLV2) {
                     minProtocolIndex = OPENSSL_OP_NO_PROTOCOL_INDEX_SSLV2;
                 }
                 if (maxProtocolIndex < OPENSSL_OP_NO_PROTOCOL_INDEX_SSLV2) {
                     maxProtocolIndex = OPENSSL_OP_NO_PROTOCOL_INDEX_SSLV2;
                 }
             } else if (p.equals(SslProtocols.SSL_v3)) {
                 if (minProtocolIndex > OPENSSL_OP_NO_PROTOCOL_INDEX_SSLV3) {
                     minProtocolIndex = OPENSSL_OP_NO_PROTOCOL_INDEX_SSLV3;
                 }
                 if (maxProtocolIndex < OPENSSL_OP_NO_PROTOCOL_INDEX_SSLV3) {
                     maxProtocolIndex = OPENSSL_OP_NO_PROTOCOL_INDEX_SSLV3;
                 }
             } else if (p.equals(SslProtocols.TLS_v1)) {
                 if (minProtocolIndex > OPENSSL_OP_NO_PROTOCOL_INDEX_TLSv1) {
                     minProtocolIndex = OPENSSL_OP_NO_PROTOCOL_INDEX_TLSv1;
                 }
                 if (maxProtocolIndex < OPENSSL_OP_NO_PROTOCOL_INDEX_TLSv1) {
                     maxProtocolIndex = OPENSSL_OP_NO_PROTOCOL_INDEX_TLSv1;
                 }
             } else if (p.equals(SslProtocols.TLS_v1_1)) {
                 if (minProtocolIndex > OPENSSL_OP_NO_PROTOCOL_INDEX_TLSv1_1) {
                     minProtocolIndex = OPENSSL_OP_NO_PROTOCOL_INDEX_TLSv1_1;
                 }
                 if (maxProtocolIndex < OPENSSL_OP_NO_PROTOCOL_INDEX_TLSv1_1) {
                     maxProtocolIndex = OPENSSL_OP_NO_PROTOCOL_INDEX_TLSv1_1;
                 }
             } else if (p.equals(SslProtocols.TLS_v1_2)) {
                 if (minProtocolIndex > OPENSSL_OP_NO_PROTOCOL_INDEX_TLSv1_2) {
                     minProtocolIndex = OPENSSL_OP_NO_PROTOCOL_INDEX_TLSv1_2;
                 }
                 if (maxProtocolIndex < OPENSSL_OP_NO_PROTOCOL_INDEX_TLSv1_2) {
                     maxProtocolIndex = OPENSSL_OP_NO_PROTOCOL_INDEX_TLSv1_2;
                 }
             } else if (!explicitDisableTLSv13 && p.equals(SslProtocols.TLS_v1_3)) {
                 if (minProtocolIndex > OPENSSL_OP_NO_PROTOCOL_INDEX_TLSv1_3) {
                     minProtocolIndex = OPENSSL_OP_NO_PROTOCOL_INDEX_TLSv1_3;
                 }
                 if (maxProtocolIndex < OPENSSL_OP_NO_PROTOCOL_INDEX_TLSv1_3) {
                     maxProtocolIndex = OPENSSL_OP_NO_PROTOCOL_INDEX_TLSv1_3;
                 }
             }
         }
         if (!isDestroyed()) {
             // Clear out options which disable protocols
             SSL.clearOptions(ssl, SSL.SSL_OP_NO_SSLv2 | SSL.SSL_OP_NO_SSLv3 | SSL.SSL_OP_NO_TLSv1 |
                     SSL.SSL_OP_NO_TLSv1_1 | SSL.SSL_OP_NO_TLSv1_2 | SSL.SSL_OP_NO_TLSv1_3);
 
             int opts = 0;
             for (int i = 0; i < minProtocolIndex; ++i) {
                 opts |= OPENSSL_OP_NO_PROTOCOLS[i];
             }
             assert maxProtocolIndex != MAX_VALUE;
             for (int i = maxProtocolIndex + 1; i < OPENSSL_OP_NO_PROTOCOLS.length; ++i) {
                 opts |= OPENSSL_OP_NO_PROTOCOLS[i];
             }
 
             // Disable protocols we do not want
             SSL.setOptions(ssl, opts);
         } else {
             throw new IllegalStateException("failed to enable protocols: " + Arrays.asList(protocols));
         }
     }
 
     @Override
     public final SSLSession getSession() {
         return session;
     }
 
     @Override
     public final synchronized void beginHandshake() throws SSLException {
         switch (handshakeState) {
             case STARTED_IMPLICITLY:
                 checkEngineClosed();
 
                 // A user did not start handshake by calling this method by him/herself,
                 // but handshake has been started already by wrap() or unwrap() implicitly.
                 // Because it's the user's first time to call this method, it is unfair to
                 // raise an exception.  From the user's standpoint, he or she never asked
                 // for renegotiation.
 
                 handshakeState = HandshakeState.STARTED_EXPLICITLY; // Next time this method is invoked by the user,
                 calculateMaxWrapOverhead();
                 // we should raise an exception.
                 break;
             case STARTED_EXPLICITLY:
                 // Nothing to do as the handshake is not done yet.
                 break;
             case FINISHED:
                 throw new SSLException("renegotiation unsupported");
             case NOT_STARTED:
                 handshakeState = HandshakeState.STARTED_EXPLICITLY;
                 if (handshake() == NEED_TASK) {
                     // Set needTask to true so getHandshakeStatus() will return the correct value.
                     needTask = true;
                 }
                 calculateMaxWrapOverhead();
                 break;
             default:
                 throw new Error();
         }
     }
 
     private void checkEngineClosed() throws SSLException {
         if (isDestroyed()) {
             throw new SSLException("engine closed");
         }
     }
 
     private static SSLEngineResult.HandshakeStatus pendingStatus(int pendingStatus) {
         // Depending on if there is something left in the BIO we need to WRAP or UNWRAP
         return pendingStatus > 0 ? NEED_WRAP : NEED_UNWRAP;
     }
 
     private static boolean isEmpty(Object[] arr) {
         return arr == null || arr.length == 0;
     }
 
     private static boolean isEmpty(byte[] cert) {
         return cert == null || cert.length == 0;
     }
 
     private SSLEngineResult.HandshakeStatus handshakeException() throws SSLException {
         if (SSL.bioLengthNonApplication(networkBIO) > 0) {
             // There is something pending, we need to consume it first via a WRAP so we don't loose anything.
             return NEED_WRAP;
         }
 
         Throwable exception = pendingException;
         assert exception != null;
         pendingException = null;
         shutdown();
         if (exception instanceof SSLHandshakeException) {
             throw (SSLHandshakeException) exception;
         }
         SSLHandshakeException e = new SSLHandshakeException("General OpenSslEngine problem");
         e.initCause(exception);
         throw e;
     }
 
     /**
      * Should be called if the handshake will be failed due a callback that throws an exception.
      * This cause will then be used to give more details as part of the {@link SSLHandshakeException}.
      */
     final void initHandshakeException(Throwable cause) {
         if (pendingException == null) {
             pendingException = cause;
         } else {
             ThrowableUtil.addSuppressed(pendingException, cause);
         }
     }
 
     private SSLEngineResult.HandshakeStatus handshake() throws SSLException {
         if (needTask) {
             return NEED_TASK;
         }
         if (handshakeState == HandshakeState.FINISHED) {
             return FINISHED;
         }
 
         checkEngineClosed();
 
         if (pendingException != null) {
             // Let's call SSL.doHandshake(...) again in case there is some async operation pending that would fill the
             // outbound buffer.
             if (SSL.doHandshake(ssl) <= 0) {
                 // Clear any error that was put on the stack by the handshake
                 SSL.clearError();
             }
             return handshakeException();
         }
 
         // Adding the OpenSslEngine to the OpenSslEngineMap so it can be used in the AbstractCertificateVerifier.
         engineMap.add(this);
 
         if (!sessionSet) {
             if (!parentContext.sessionContext().setSessionFromCache(ssl, session, getPeerHost(), getPeerPort())) {
                 // The session was not reused via the cache. Call prepareHandshake() to ensure we remove all previous
                 // stored key-value pairs.
                 session.prepareHandshake();
             }
             sessionSet = true;
         }
 
         int code = SSL.doHandshake(ssl);
         if (code <= 0) {
             int sslError = SSL.getError(ssl, code);
             if (sslError == SSL.SSL_ERROR_WANT_READ || sslError == SSL.SSL_ERROR_WANT_WRITE) {
                 return pendingStatus(SSL.bioLengthNonApplication(networkBIO));
             }
 
             if (sslError == SSL.SSL_ERROR_WANT_X509_LOOKUP ||
                     sslError == SSL.SSL_ERROR_WANT_CERTIFICATE_VERIFY ||
                     sslError == SSL.SSL_ERROR_WANT_PRIVATE_KEY_OPERATION) {
                 return NEED_TASK;
             }
 
             int errorNumber = SSL.getLastErrorNumber();
             if (needWrapAgain(errorNumber)) {
                 // There is something that needs to be send to the remote peer before we can teardown.
                 // This is most likely some alert.
                 return NEED_WRAP;
             }
             // Check if we have a pending exception that was created during the handshake and if so throw it after
             // shutdown the connection.
             if (pendingException != null) {
                 return handshakeException();
             }
 
             // Everything else is considered as error
             throw shutdownWithError("SSL_do_handshake", sslError, errorNumber);
         }
         // We have produced more data as part of the handshake if this is the case the user should call wrap(...)
         if (SSL.bioLengthNonApplication(networkBIO) > 0) {
             return NEED_WRAP;
         }
         // if SSL_do_handshake returns > 0 or sslError == SSL.SSL_ERROR_NAME it means the handshake was finished.
         session.handshakeFinished(SSL.getSessionId(ssl), SSL.getCipherForSSL(ssl), SSL.getVersion(ssl),
                 SSL.getPeerCertificate(ssl), SSL.getPeerCertChain(ssl),
                 SSL.getTime(ssl) * 1000L, parentContext.sessionTimeout() * 1000L);
         selectApplicationProtocol();
         return FINISHED;
     }
 
     private SSLEngineResult.HandshakeStatus mayFinishHandshake(
             SSLEngineResult.HandshakeStatus hs, int bytesConsumed, int bytesProduced) throws SSLException {
         return hs == NEED_UNWRAP && bytesProduced > 0 || hs == NEED_WRAP && bytesConsumed > 0 ?
             handshake() : mayFinishHandshake(hs != FINISHED ? getHandshakeStatus() : FINISHED);
     }
 
     private SSLEngineResult.HandshakeStatus mayFinishHandshake(SSLEngineResult.HandshakeStatus status)
             throws SSLException {
         if (status == NOT_HANDSHAKING) {
             if (handshakeState != HandshakeState.FINISHED) {
                 // If the status was NOT_HANDSHAKING and we not finished the handshake we need to call
                 // SSL_do_handshake() again
                 return handshake();
             }
             if (!isDestroyed() && SSL.bioLengthNonApplication(networkBIO) > 0) {
                 // We have something left that needs to be wrapped.
                 return NEED_WRAP;
             }
         }
         return status;
     }
 
     @Override
     public final synchronized SSLEngineResult.HandshakeStatus getHandshakeStatus() {
         // Check if we are in the initial handshake phase or shutdown phase
         if (needPendingStatus()) {
             if (needTask) {
                 // There is a task outstanding
                 return NEED_TASK;
             }
             return pendingStatus(SSL.bioLengthNonApplication(networkBIO));
         }
         return NOT_HANDSHAKING;
     }
 
     private SSLEngineResult.HandshakeStatus getHandshakeStatus(int pending) {
         // Check if we are in the initial handshake phase or shutdown phase
         if (needPendingStatus()) {
             if (needTask) {
                 // There is a task outstanding
                 return NEED_TASK;
             }
             return pendingStatus(pending);
         }
         return NOT_HANDSHAKING;
     }
 
     private boolean needPendingStatus() {
         return handshakeState != HandshakeState.NOT_STARTED && !isDestroyed()
                 && (handshakeState != HandshakeState.FINISHED || isInboundDone() || isOutboundDone());
     }
 
     /**
      * Converts the specified OpenSSL cipher suite to the Java cipher suite.
      */
     private String toJavaCipherSuite(String openSslCipherSuite) {
         if (openSslCipherSuite == null) {
             return null;
         }
 
         String version = SSL.getVersion(ssl);
         String prefix = toJavaCipherSuitePrefix(version);
         return CipherSuiteConverter.toJava(openSslCipherSuite, prefix);
     }
 
     /**
      * Converts the protocol version string returned by {@link SSL#getVersion(long)} to protocol family string.
      */
     private static String toJavaCipherSuitePrefix(String protocolVersion) {
         final char c;
         if (protocolVersion == null || protocolVersion.isEmpty()) {
             c = 0;
         } else {
             c = protocolVersion.charAt(0);
         }
 
         switch (c) {
             case 'T':
                 return "TLS";
             case 'S':
                 return "SSL";
             default:
                 return "UNKNOWN";
         }
     }
 
     @Override
     public final void setUseClientMode(boolean clientMode) {
         if (clientMode != this.clientMode) {
             throw new UnsupportedOperationException();
         }
     }
 
     @Override
     public final boolean getUseClientMode() {
         return clientMode;
     }
 
     @Override
     public final void setNeedClientAuth(boolean b) {
         setClientAuth(b ? ClientAuth.REQUIRE : ClientAuth.NONE);
     }
 
     @Override
     public final boolean getNeedClientAuth() {
         return clientAuth == ClientAuth.REQUIRE;
     }
 
     @Override
     public final void setWantClientAuth(boolean b) {
         setClientAuth(b ? ClientAuth.OPTIONAL : ClientAuth.NONE);
     }
 
     @Override
     public final boolean getWantClientAuth() {
         return clientAuth == ClientAuth.OPTIONAL;
     }
 
     /**
      * See <a href="https://www.openssl.org/docs/man1.0.2/ssl/SSL_set_verify.html">SSL_set_verify</a> and
      * {@link SSL#setVerify(long, int, int)}.
      */
     @UnstableApi
     public final synchronized void setVerify(int verifyMode, int depth) {
         if (!isDestroyed()) {
             SSL.setVerify(ssl, verifyMode, depth);
         }
     }
 
     private void setClientAuth(ClientAuth mode) {
         if (clientMode) {
             return;
         }
         synchronized (this) {
             if (clientAuth == mode) {
                 // No need to issue any JNI calls if the mode is the same
                 return;
             }
             if (!isDestroyed()) {
                 switch (mode) {
                     case NONE:
                         SSL.setVerify(ssl, SSL.SSL_CVERIFY_NONE, ReferenceCountedOpenSslContext.VERIFY_DEPTH);
                         break;
                     case REQUIRE:
                         SSL.setVerify(ssl, SSL.SSL_CVERIFY_REQUIRED, ReferenceCountedOpenSslContext.VERIFY_DEPTH);
                         break;
                     case OPTIONAL:
                         SSL.setVerify(ssl, SSL.SSL_CVERIFY_OPTIONAL, ReferenceCountedOpenSslContext.VERIFY_DEPTH);
                         break;
                     default:
                         throw new Error(mode.toString());
                 }
             }
             clientAuth = mode;
         }
     }
 
     @Override
     public final void setEnableSessionCreation(boolean b) {
         if (b) {
             throw new UnsupportedOperationException();
         }
     }
 
     @Override
     public final boolean getEnableSessionCreation() {
         return false;
     }
 
     @SuppressJava6Requirement(reason = "Usage guarded by java version check")
     @Override
     public final synchronized SSLParameters getSSLParameters() {
         SSLParameters sslParameters = super.getSSLParameters();
 
         int version = PlatformDependent.javaVersion();
         if (version >= 7) {
             Java7SslParametersUtils.setEndpointIdentificationAlgorithm(sslParameters, endpointIdentificationAlgorithm);
             Java7SslParametersUtils.setAlgorithmConstraints(sslParameters, algorithmConstraints);
             if (version >= 8) {
                 if (sniHostNames != null) {
                     Java8SslUtils.setSniHostNames(sslParameters, sniHostNames);
                 }
                 if (!isDestroyed()) {
                     Java8SslUtils.setUseCipherSuitesOrder(
                             sslParameters, (SSL.getOptions(ssl) & SSL.SSL_OP_CIPHER_SERVER_PREFERENCE) != 0);
                 }
 
                 Java8SslUtils.setSNIMatchers(sslParameters, matchers);
             }
         }
         return sslParameters;
     }
 
     @SuppressJava6Requirement(reason = "Usage guarded by java version check")
     @Override
     public final synchronized void setSSLParameters(SSLParameters sslParameters) {
         int version = PlatformDependent.javaVersion();
         if (version >= 7) {
             if (sslParameters.getAlgorithmConstraints() != null) {
                 throw new IllegalArgumentException("AlgorithmConstraints are not supported.");
             }
 
             boolean isDestroyed = isDestroyed();
             if (version >= 8) {
                 if (!isDestroyed) {
                     if (clientMode) {
                         final List<String> sniHostNames = Java8SslUtils.getSniHostNames(sslParameters);
                         for (String name: sniHostNames) {
                             SSL.setTlsExtHostName(ssl, name);
                         }
                         this.sniHostNames = sniHostNames;
                     }
                     if (Java8SslUtils.getUseCipherSuitesOrder(sslParameters)) {
                         SSL.setOptions(ssl, SSL.SSL_OP_CIPHER_SERVER_PREFERENCE);
                     } else {
                         SSL.clearOptions(ssl, SSL.SSL_OP_CIPHER_SERVER_PREFERENCE);
                     }
                 }
                 matchers = sslParameters.getSNIMatchers();
             }
 
             final String endpointIdentificationAlgorithm = sslParameters.getEndpointIdentificationAlgorithm();
             if (!isDestroyed) {
                 configureEndpointVerification(endpointIdentificationAlgorithm);
             }
             this.endpointIdentificationAlgorithm = endpointIdentificationAlgorithm;
             algorithmConstraints = sslParameters.getAlgorithmConstraints();
         }
         super.setSSLParameters(sslParameters);
     }
 
     private void configureEndpointVerification(String endpointIdentificationAlgorithm) {
         // If the user asks for hostname verification we must ensure we verify the peer.
         // If the user disables hostname verification we leave it up to the user to change the mode manually.
         if (clientMode && isEndPointVerificationEnabled(endpointIdentificationAlgorithm)) {
             SSL.setVerify(ssl, SSL.SSL_CVERIFY_REQUIRED, -1);
         }
     }
 
     private static boolean isEndPointVerificationEnabled(String endPointIdentificationAlgorithm) {
         return endPointIdentificationAlgorithm != null && !endPointIdentificationAlgorithm.isEmpty();
     }
 
     private boolean isDestroyed() {
         return destroyed;
     }
 
     final boolean checkSniHostnameMatch(byte[] hostname) {
         return Java8SslUtils.checkSniHostnameMatch(matchers, hostname);
     }
 
     @Override
     public String getNegotiatedApplicationProtocol() {
         return applicationProtocol;
     }
 
     private static long bufferAddress(ByteBuffer b) {
         assert b.isDirect();
         if (PlatformDependent.hasUnsafe()) {
             return PlatformDependent.directBufferAddress(b);
         }
         return Buffer.address(b);
     }
 
     /**
      * Select the application protocol used.
      */
     private void selectApplicationProtocol() throws SSLException {
         ApplicationProtocolConfig.SelectedListenerFailureBehavior behavior = apn.selectedListenerFailureBehavior();
         List<String> protocols = apn.protocols();
         String applicationProtocol;
         switch (apn.protocol()) {
             case NONE:
                 break;
             // We always need to check for applicationProtocol == null as the remote peer may not support
             // the TLS extension or may have returned an empty selection.
             case ALPN:
                 applicationProtocol = SSL.getAlpnSelected(ssl);
                 if (applicationProtocol != null) {
                     ReferenceCountedOpenSslEngine.this.applicationProtocol = selectApplicationProtocol(
                             protocols, behavior, applicationProtocol);
                 }
                 break;
             case NPN:
                 applicationProtocol = SSL.getNextProtoNegotiated(ssl);
                 if (applicationProtocol != null) {
                     ReferenceCountedOpenSslEngine.this.applicationProtocol = selectApplicationProtocol(
                             protocols, behavior, applicationProtocol);
                 }
                 break;
             case NPN_AND_ALPN:
                 applicationProtocol = SSL.getAlpnSelected(ssl);
                 if (applicationProtocol == null) {
                     applicationProtocol = SSL.getNextProtoNegotiated(ssl);
                 }
                 if (applicationProtocol != null) {
                     ReferenceCountedOpenSslEngine.this.applicationProtocol = selectApplicationProtocol(
                             protocols, behavior, applicationProtocol);
                 }
                 break;
             default:
                 throw new Error();
         }
     }
 
     private String selectApplicationProtocol(List<String> protocols,
                                              ApplicationProtocolConfig.SelectedListenerFailureBehavior behavior,
                                              String applicationProtocol) throws SSLException {
         if (behavior == ApplicationProtocolConfig.SelectedListenerFailureBehavior.ACCEPT) {
             return applicationProtocol;
         } else {
             int size = protocols.size();
             assert size > 0;
             if (protocols.contains(applicationProtocol)) {
                 return applicationProtocol;
             } else {
                 if (behavior == ApplicationProtocolConfig.SelectedListenerFailureBehavior.CHOOSE_MY_LAST_PROTOCOL) {
                     return protocols.get(size - 1);
                 } else {
                     throw new SSLException("unknown protocol " + applicationProtocol);
                 }
             }
         }
     }
 
     private static final X509Certificate[] JAVAX_CERTS_NOT_SUPPORTED = new X509Certificate[0];
 
     private final class DefaultOpenSslSession implements OpenSslInternalSession {
         private final OpenSslSessionContext sessionContext;
 
         // These are guarded by synchronized(OpenSslEngine.this) as handshakeFinished() may be triggered by any
         // thread.
         private X509Certificate[] x509PeerCerts;
         private Certificate[] peerCerts;
 
         private boolean valid = true;
         private String protocol;
         private String cipher;
         private OpenSslSessionId id = OpenSslSessionId.NULL_ID;
         private long creationTime;
 
         // Updated once a new handshake is started and so the SSLSession reused.
         private long lastAccessed = -1;
 
         private volatile int applicationBufferSize = MAX_PLAINTEXT_LENGTH;
         private volatile Certificate[] localCertificateChain;
         private volatile Map<String, Object> keyValueStorage = new ConcurrentHashMap<String, Object>();
 
         DefaultOpenSslSession(OpenSslSessionContext sessionContext) {
             this.sessionContext = sessionContext;
         }
 
         private SSLSessionBindingEvent newSSLSessionBindingEvent(String name) {
             return new SSLSessionBindingEvent(session, name);
         }
 
         @Override
         public void prepareHandshake() {
             keyValueStorage.clear();
         }
 
         @Override
         public void setSessionDetails(
                 long creationTime, long lastAccessedTime, OpenSslSessionId sessionId,
                 Map<String, Object> keyValueStorage) {
             synchronized (ReferenceCountedOpenSslEngine.this) {
                 if (this.id == OpenSslSessionId.NULL_ID) {
                     this.id = sessionId;
                     this.creationTime = creationTime;
                     this.lastAccessed = lastAccessedTime;
 
                     // Update the key value storage. It's fine to just drop the previous stored values on the floor
                     // as the JDK does the same in the sense that it will use a new SSLSessionImpl instance once the
                     // handshake was done
                     this.keyValueStorage = keyValueStorage;
                 }
             }
         }
 
         @Override
         public Map<String, Object> keyValueStorage() {
             return keyValueStorage;
         }
 
         @Override
         public OpenSslSessionId sessionId() {
             synchronized (ReferenceCountedOpenSslEngine.this) {
                 if (this.id == OpenSslSessionId.NULL_ID && !isDestroyed()) {
                     byte[] sessionId = SSL.getSessionId(ssl);
                     if (sessionId != null) {
                         id = new OpenSslSessionId(sessionId);
                     }
                 }
 
                 return id;
             }
         }
 
         @Override
         public void setLocalCertificate(Certificate[] localCertificate) {
             this.localCertificateChain = localCertificate;
         }
 
         @Override
         public byte[] getId() {
             return sessionId().cloneBytes();
         }
 
         @Override
         public OpenSslSessionContext getSessionContext() {
             return sessionContext;
         }
 
         @Override
         public long getCreationTime() {
             synchronized (ReferenceCountedOpenSslEngine.this) {
                 return creationTime;
             }
         }
 
         @Override
         public void setLastAccessedTime(long time) {
             synchronized (ReferenceCountedOpenSslEngine.this) {
                 this.lastAccessed = time;
             }
         }
 
         @Override
         public long getLastAccessedTime() {
             // if lastAccessed is -1 we will just return the creation time as the handshake was not started yet.
             synchronized (ReferenceCountedOpenSslEngine.this) {
                 return lastAccessed == -1 ? creationTime : lastAccessed;
             }
         }
 
         @Override
         public void invalidate() {
             synchronized (ReferenceCountedOpenSslEngine.this) {
                 valid = false;
                 sessionContext.removeFromCache(id);
             }
         }
 
         @Override
         public boolean isValid() {
             synchronized (ReferenceCountedOpenSslEngine.this) {
                 return valid || sessionContext.isInCache(id);
             }
         }
 
         @Override
         public void putValue(String name, Object value) {
             checkNotNull(name, "name");
             checkNotNull(value, "value");
 
             final Object old = keyValueStorage.put(name, value);
             if (value instanceof SSLSessionBindingListener) {
                 // Use newSSLSessionBindingEvent so we always use the wrapper if needed.
                 ((SSLSessionBindingListener) value).valueBound(newSSLSessionBindingEvent(name));
             }
             notifyUnbound(old, name);
         }
 
         @Override
         public Object getValue(String name) {
             checkNotNull(name, "name");
             return keyValueStorage.get(name);
         }
 
         @Override
         public void removeValue(String name) {
             checkNotNull(name, "name");
             final Object old = keyValueStorage.remove(name);
             notifyUnbound(old, name);
         }
 
         @Override
         public String[] getValueNames() {
             return keyValueStorage.keySet().toArray(EMPTY_STRINGS);
         }
 
         private void notifyUnbound(Object value, String name) {
             if (value instanceof SSLSessionBindingListener) {
                 // Use newSSLSessionBindingEvent so we always use the wrapper if needed.
                 ((SSLSessionBindingListener) value).valueUnbound(newSSLSessionBindingEvent(name));
             }
         }
 
         /**
          * Finish the handshake and so init everything in the {@link OpenSslInternalSession} that should be accessible
          * by the user.
          */
         @Override
         public void handshakeFinished(byte[] id, String cipher, String protocol, byte[] peerCertificate,
                                       byte[][] peerCertificateChain, long creationTime, long timeout)
                 throws SSLException {
             synchronized (ReferenceCountedOpenSslEngine.this) {
                 if (!isDestroyed()) {
                     if (this.id == OpenSslSessionId.NULL_ID) {
                         // if the handshake finished and it was not a resumption let ensure we try to set the id
 
                         this.id = id == null ? OpenSslSessionId.NULL_ID : new OpenSslSessionId(id);
                         // Once the handshake was done the lastAccessed and creationTime should be the same if we
                         // did not set it earlier via setSessionDetails(...)
                         this.creationTime = lastAccessed = creationTime;
                     }
                     this.cipher = toJavaCipherSuite(cipher);
                     this.protocol = protocol;
 
                     if (clientMode) {
                         if (isEmpty(peerCertificateChain)) {
                             peerCerts = EmptyArrays.EMPTY_CERTIFICATES;
                             if (OpenSsl.JAVAX_CERTIFICATE_CREATION_SUPPORTED) {
                                 x509PeerCerts = EmptyArrays.EMPTY_JAVAX_X509_CERTIFICATES;
                             } else {
                                 x509PeerCerts = JAVAX_CERTS_NOT_SUPPORTED;
                             }
                         } else {
                             peerCerts = new Certificate[peerCertificateChain.length];
                             if (OpenSsl.JAVAX_CERTIFICATE_CREATION_SUPPORTED) {
                                 x509PeerCerts = new X509Certificate[peerCertificateChain.length];
                             } else {
                                 x509PeerCerts = JAVAX_CERTS_NOT_SUPPORTED;
                             }
                             initCerts(peerCertificateChain, 0);
                         }
                     } else {
                         // if used on the server side SSL_get_peer_cert_chain(...) will not include the remote peer
                         // certificate. We use SSL_get_peer_certificate to get it in this case and add it to our
                         // array later.
                         //
                         // See https://www.openssl.org/docs/ssl/SSL_get_peer_cert_chain.html
                         if (isEmpty(peerCertificate)) {
                             peerCerts = EmptyArrays.EMPTY_CERTIFICATES;
                             x509PeerCerts = EmptyArrays.EMPTY_JAVAX_X509_CERTIFICATES;
                         } else {
                             if (isEmpty(peerCertificateChain)) {
                                 peerCerts = new Certificate[] {new LazyX509Certificate(peerCertificate)};
                                 if (OpenSsl.JAVAX_CERTIFICATE_CREATION_SUPPORTED) {
                                     x509PeerCerts = new X509Certificate[] {
                                             new LazyJavaxX509Certificate(peerCertificate)
                                     };
                                 } else {
                                     x509PeerCerts = JAVAX_CERTS_NOT_SUPPORTED;
                                 }
                             } else {
                                 peerCerts = new Certificate[peerCertificateChain.length + 1];
                                 peerCerts[0] = new LazyX509Certificate(peerCertificate);
 
                                 if (OpenSsl.JAVAX_CERTIFICATE_CREATION_SUPPORTED) {
                                     x509PeerCerts = new X509Certificate[peerCertificateChain.length + 1];
                                     x509PeerCerts[0] = new LazyJavaxX509Certificate(peerCertificate);
                                 } else {
                                     x509PeerCerts = JAVAX_CERTS_NOT_SUPPORTED;
                                 }
 
                                 initCerts(peerCertificateChain, 1);
                             }
                         }
                     }
 
                     calculateMaxWrapOverhead();
 
                     handshakeState = HandshakeState.FINISHED;
                 } else {
                     throw new SSLException("Already closed");
                 }
             }
         }
 
         private void initCerts(byte[][] chain, int startPos) {
             for (int i = 0; i < chain.length; i++) {
                 int certPos = startPos + i;
                 peerCerts[certPos] = new LazyX509Certificate(chain[i]);
                 if (x509PeerCerts != JAVAX_CERTS_NOT_SUPPORTED) {
                     x509PeerCerts[certPos] = new LazyJavaxX509Certificate(chain[i]);
                 }
             }
         }
 
         @Override
         public Certificate[] getPeerCertificates() throws SSLPeerUnverifiedException {
             synchronized (ReferenceCountedOpenSslEngine.this) {
                 if (isEmpty(peerCerts)) {
                     throw new SSLPeerUnverifiedException("peer not verified");
                 }
                 return peerCerts.clone();
             }
         }
 
         @Override
         public boolean hasPeerCertificates() {
             synchronized (ReferenceCountedOpenSslEngine.this) {
                 return !isEmpty(peerCerts);
             }
         }
 
         @Override
         public Certificate[] getLocalCertificates() {
             Certificate[] localCerts = this.localCertificateChain;
             if (localCerts == null) {
                 return null;
             }
             return localCerts.clone();
         }
 
         @Override
         public X509Certificate[] getPeerCertificateChain() throws SSLPeerUnverifiedException {
             synchronized (ReferenceCountedOpenSslEngine.this) {
                 if (x509PeerCerts == JAVAX_CERTS_NOT_SUPPORTED) {
                     // Not supported by the underlying JDK, so just throw. This is fine in terms of the API
                     // contract. See SSLSession.html#getPeerCertificateChain().
                     throw new UnsupportedOperationException();
                 }
                 if (isEmpty(x509PeerCerts)) {
                     throw new SSLPeerUnverifiedException("peer not verified");
                 }
                 return x509PeerCerts.clone();
             }
         }
 
         @Override
         public Principal getPeerPrincipal() throws SSLPeerUnverifiedException {
             Certificate[] peer = getPeerCertificates();
             // No need for null or length > 0 is needed as this is done in getPeerCertificates()
             // already.
             return ((java.security.cert.X509Certificate) peer[0]).getSubjectX500Principal();
         }
 
         @Override
         public Principal getLocalPrincipal() {
             Certificate[] local = this.localCertificateChain;
             if (local == null || local.length == 0) {
                 return null;
             }
             return ((java.security.cert.X509Certificate) local[0]).getSubjectX500Principal();
         }
 
         @Override
         public String getCipherSuite() {
             synchronized (ReferenceCountedOpenSslEngine.this) {
                 if (cipher == null) {
                     return SslUtils.INVALID_CIPHER;
                 }
                 return cipher;
             }
         }
 
         @Override
         public String getProtocol() {
             String protocol = this.protocol;
             if (protocol == null) {
                 synchronized (ReferenceCountedOpenSslEngine.this) {
                     if (!isDestroyed()) {
                         protocol = SSL.getVersion(ssl);
                     } else {
                         protocol = StringUtil.EMPTY_STRING;
                     }
                 }
             }
             return protocol;
         }
 
         @Override
         public String getPeerHost() {
             return ReferenceCountedOpenSslEngine.this.getPeerHost();
         }
 
         @Override
         public int getPeerPort() {
             return ReferenceCountedOpenSslEngine.this.getPeerPort();
         }
 
         @Override
         public int getPacketBufferSize() {
             return SSL.SSL_MAX_ENCRYPTED_LENGTH;
         }
 
         @Override
         public int getApplicationBufferSize() {
             return applicationBufferSize;
         }
 
         @Override
         public void tryExpandApplicationBufferSize(int packetLengthDataOnly) {
             if (packetLengthDataOnly > MAX_PLAINTEXT_LENGTH && applicationBufferSize != MAX_RECORD_SIZE) {
                 applicationBufferSize = MAX_RECORD_SIZE;
             }
         }
 
         @Override
         public String toString() {
             return "DefaultOpenSslSession{" +
                     "sessionContext=" + sessionContext +
                     ", id=" + id +
                     '}';
         }
 
         @Override
         public int hashCode() {
             return sessionId().hashCode();
         }
 
         @Override
         public boolean equals(Object o) {
             if (o == this) {
                 return true;
             }
             // We trust all sub-types as we use different types but the interface is package-private
             if (!(o instanceof OpenSslInternalSession)) {
                 return false;
             }
             return sessionId().equals(((OpenSslInternalSession) o).sessionId());
         }
     }
 
     private interface NativeSslException {
         int errorCode();
     }
 
     private static final class OpenSslException extends SSLException implements NativeSslException {
         private final int errorCode;
 
         OpenSslException(String reason, int errorCode) {
             super(reason);
             this.errorCode = errorCode;
         }
 
         @Override
         public int errorCode() {
             return errorCode;
         }
     }
 
     private static final class OpenSslHandshakeException extends SSLHandshakeException implements NativeSslException {
         private final int errorCode;
 
         OpenSslHandshakeException(String reason, int errorCode) {
             super(reason);
             this.errorCode = errorCode;
         }
 
         @Override
         public int errorCode() {
             return errorCode;
         }
     }
 }